|
80,000
80,000 (eighty thousand) is the natural number after 79,999 and before 80,001. Selected numbers in the range 80,000–89,999 * 80,286 = model number of the Intel 80286 chip * 80,386 = model number of the Intel 80386 chip * 82,467 = number of square (0,1)-matrices without zero rows and with exactly 6 entries equal to 1 * 80,486 = model number of the Intel 80486 chip * 80,782 = Pell number ''P''14 * 82,000 = the only currently known number greater than 1 that can be written in bases from 2 through 5 using only 0s and 1s. * 82,025 = number of primes \leq 2^. * 82,656 = Kaprekar number: 826562 = 6832014336; 68320 + 14336 = 82656 * 82,944 = 3- smooth number: 210 × 34 * 83,097 = Riordan number * 83,160 = highly composite number * 83,357 = Friedman prime * 83,521 = 174 * 84,187 – number of parallelogram polyominoes with 15 cells. * 85,085 = product of five consecutive primes: 5 × 7 × 11 × 13 × 17 * 85,184 = 443 * 86,400 = seconds in a day: 24 × 60 × 60 and common DNS defau ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
80,000 Hours
80,000 Hours is a London-based nonprofit organisation that conducts research on which careers have the largest positive social impact and provides career advice based on that research. It provides this advice on their website and podcast, and through one-on-one advice sessions. The organisation is part of the Centre for Effective Altruism, affiliated with the Oxford Uehiro Centre for Practical Ethics. The organisation's name refers to the typical amount of time someone spends working over a lifetime. Principles According to 80,000 Hours, some careers aimed at doing good are far more effective than others. They evaluate problems people can focus on solving in terms of their "scale", "neglectedness", and "solvability", while career paths are rated on their potential for immediate social impact, on how well they set someone up to have an impact later on, and on personal fit with the reader. The group emphasises that the positive impact of choosing a certain occupation should ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natural Number
In mathematics, the natural numbers are those numbers used for counting (as in "there are ''six'' coins on the table") and ordering (as in "this is the ''third'' largest city in the country"). Numbers used for counting are called ''Cardinal number, cardinal numbers'', and numbers used for ordering are called ''Ordinal number, ordinal numbers''. Natural numbers are sometimes used as labels, known as ''nominal numbers'', having none of the properties of numbers in a mathematical sense (e.g. sports Number (sports), jersey numbers). Some definitions, including the standard ISO/IEC 80000, ISO 80000-2, begin the natural numbers with , corresponding to the non-negative integers , whereas others start with , corresponding to the positive integers Texts that exclude zero from the natural numbers sometimes refer to the natural numbers together with zero as the whole numbers, while in other writings, that term is used instead for the integers (including negative integers). The natural ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
70,000
70,000 (seventy thousand) is the natural number that comes after 69,999 and before 70,001. It is a round number. Selected numbers in the range 70001–79999 70001 to 70999 71000 to 71999 * 71656 = pentagonal pyramidal number 72000 to 72999 73000 to 73999 * 73296 = is the smallest number ''n'', for which ''n''−3, ''n''−2, ''n''−1, ''n''+1, ''n''+2, ''n''+3 are all Sphenic number. * 73440 = 15 × 16 × 17 × 18 * 73712 = number of ''n''-Queens Problem solutions for ''n'' = 13 * 73728 = 3- smooth number 74000 to 74999 * 74088 = 423 * 74205 = registry number of the USS Defiant on ''Star Trek: Deep Space Nine'' * 74353 = Friedman prime * 74656 = registry number of the USS Voyager on '' Star Trek: Voyager'' * 74897 = Friedman prime 75000 to 75999 * 75025 = Fibonacci number, Markov number * 75361 = Carmichael number 76000 to 76999 * 76084 = amicable number with 63020 * 76424 = tetranacci number 77000 to 77999 * 77777 = repdigit * 77778 = Kaprekar number 7800 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intel 80286
The Intel 80286 (also marketed as the iAPX 286 and often called Intel 286) is a 16-bit microprocessor that was introduced on February 1, 1982. It was the first 8086-based CPU with separate, non-multiplexed address and data buses and also the first with memory management and wide protection abilities. The 80286 used approximately 134,000 transistors in its original nMOS (HMOS) incarnation and, just like the contemporary 80186, it could correctly execute most software written for the earlier Intel 8086 and 8088 processors. The 80286 was employed for the IBM PC/AT, introduced in 1984, and then widely used in most PC/AT compatible computers until the early 1990s. In 1987, Intel shipped its five-millionth 80286 microprocessor. History and performance Intel's first 80286 chips were specified for a maximum clockrate of 5, 6 or 8 MHz and later releases for 12.5 MHz. AMD and Harris later produced 16 MHz, 20 MHz and 25 MHz parts, respectively. Intersil and Fuj ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intel 80386
The Intel 386, originally released as 80386 and later renamed i386, is a 32-bit microprocessor introduced in 1985. The first versions had 275,000 transistorsmit.edu—The Future of FPGAs (Cornell) October 11, 2012 and were the CPU of many s and high-end s of the time. As the original implementation of the |
Intel 80486
The Intel 486, officially named i486 and also known as 80486, is a microprocessor. It is a higher-performance follow-up to the Intel 386. The i486 was introduced in 1989. It represents the fourth generation of binary compatible CPUs following the 8086 of 1978, the Intel 80286 of 1982, and 1985's i386. It was the first tightly- pipelined x86 design as well as the first x86 chip to include more than one million transistors. It offered a large on-chip cache and an integrated floating-point unit. A typical 50 MHz i486 executes around 40 million instructions per second (MIPS), reaching 50 MIPS peak performance. It is approximately twice as fast as the i386 or i286 per clock cycle. The i486's improved performance is thanks to its five-stage pipeline with all stages bound to a single cycle. The enhanced FPU unit on the chip was significantly faster than the i387 FPU per cycle. The intel 80387 FPU ("i387") was a separate, optional math coprocessor that was installed in a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pell Number
In mathematics, the Pell numbers are an infinite sequence of integers, known since ancient times, that comprise the denominators of the closest rational approximations to the square root of 2. This sequence of approximations begins , , , , and , so the sequence of Pell numbers begins with 1, 2, 5, 12, and 29. The numerators of the same sequence of approximations are half the companion Pell numbers or Pell–Lucas numbers; these numbers form a second infinite sequence that begins with 2, 6, 14, 34, and 82. Both the Pell numbers and the companion Pell numbers may be calculated by means of a recurrence relation similar to that for the Fibonacci numbers, and both sequences of numbers grow exponentially, proportionally to powers of the silver ratio 1 + . As well as being used to approximate the square root of two, Pell numbers can be used to find square triangular numbers, to construct integer approximations to the right isosceles triangle, and to solve certain combinat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kaprekar Number
In mathematics, a natural number in a given number base is a p-Kaprekar number if the representation of its square in that base can be split into two parts, where the second part has p digits, that add up to the original number. The numbers are named after D. R. Kaprekar. Definition and properties Let n be a natural number. We define the Kaprekar function for base b > 1 and power p > 0 F_ : \mathbb \rightarrow \mathbb to be the following: :F_(n) = \alpha + \beta, where \beta = n^2 \bmod b^p and :\alpha = \frac A natural number n is a p-Kaprekar number if it is a fixed point for F_, which occurs if F_(n) = n. 0 and 1 are trivial Kaprekar numbers for all b and p, all other Kaprekar numbers are nontrivial Kaprekar numbers. For example, in base 10, 45 is a 2-Kaprekar number, because : \beta = n^2 \bmod b^p = 45^2 \bmod 10^2 = 25 : \alpha = \frac = \frac = 20 : F_(45) = \alpha + \beta = 20 + 25 = 45 A natural number n is a sociable Kaprekar number if it is a periodic point for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Smooth Number
In number theory, an ''n''-smooth (or ''n''-friable) number is an integer whose prime factors are all less than or equal to ''n''. For example, a 7-smooth number is a number whose every prime factor is at most 7, so 49 = 72 and 15750 = 2 × 32 × 53 × 7 are both 7-smooth, while 11 and 702 = 2 × 33 × 13 are not 7-smooth. The term seems to have been coined by Leonard Adleman. Smooth numbers are especially important in cryptography, which relies on factorization of integers. The 2-smooth numbers are just the powers of 2, while 5-smooth numbers are known as regular numbers. Definition A positive integer is called B-smooth if none of its prime factors are greater than B. For example, 1,620 has prime factorization 22 × 34 × 5; therefore 1,620 is 5-smooth because none of its prime factors are greater than 5. This definition includes numbers that lack some of the smaller prime factors; for example, both 10 and 12 are 5-smooth, even though they miss out the prime factors 3 and 5, resp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
A005043
A, or a, is the first letter and the first vowel of the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is ''a'' (pronounced ), plural ''aes''. It is similar in shape to the Ancient Greek letter alpha, from which it derives. The uppercase version consists of the two slanting sides of a triangle, crossed in the middle by a horizontal bar. The lowercase version can be written in two forms: the double-storey a and single-storey ɑ. The latter is commonly used in handwriting and fonts based on it, especially fonts intended to be read by children, and is also found in italic type. In English grammar, " a", and its variant " an", are indefinite articles. History The earliest certain ancestor of "A" is aleph (also written 'aleph), the first letter of the Phoenician alphabet, which consisted entirely of consonants (for that reason, it is also called an abjad to distinguish it fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Highly Composite Number
__FORCETOC__ A highly composite number is a positive integer with more divisors than any smaller positive integer has. The related concept of largely composite number refers to a positive integer which has at least as many divisors as any smaller positive integer. The name can be somewhat misleading, as the first two highly composite numbers (1 and 2) are not actually composite numbers; however, all further terms are. The late mathematician Jean-Pierre Kahane has suggested that Plato must have known about highly composite numbers as he deliberately chose 5040 as the ideal number of citizens in a city as 5040 has more divisors than any numbers less than it. Ramanujan wrote and titled his paper on the subject in 1915. Examples The initial or smallest 38 highly composite numbers are listed in the table below . The number of divisors is given in the column labeled ''d''(''n''). Asterisks indicate superior highly composite numbers. The divisors of the first 15 highly composite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Friedman Prime
A Friedman number is an integer, which represented in a given numeral system, is the result of a non-trivial expression using all its own digits in combination with any of the four basic arithmetic operators (+, −, ×, ÷), additive inverses, parentheses, exponentiation, and concatenation. Here, non-trivial means that at least one operation besides concatenation is used. Leading zeros cannot be used, since that would also result in trivial Friedman numbers, such as 024 = 20 + 4. For example, 347 is a Friedman number in the decimal numeral system, since 347 = 73 + 4. The decimal Friedman numbers are: :25, 121, 125, 126, 127, 128, 153, 216, 289, 343, 347, 625, 688, 736, 1022, 1024, 1206, 1255, 1260, 1285, 1296, 1395, 1435, 1503, 1530, 1792, 1827, 2048, 2187, 2349, 2500, 2501, 2502, 2503, 2504, 2505, 2506, 2507, 2508, 2509, 2592, 2737, 2916, ... . Friedman numbers are named after Erich Friedman, a now-retired mathematics professor at Stetson University, located in DeLand, Flo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
