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Centered Pentagonal Number
In mathematics, a centered pentagonal number is a centered polygonal number, centered figurate number that represents a pentagon with a dot in the center and all other dots surrounding the center in successive pentagonal layers. The centered pentagonal number for ''n'' is given by the formula :P_=, n\geq1 The first few centered pentagonal numbers are 1 (number), 1, 6 (number), 6, 16 (number), 16, 31 (number), 31, 51 (number), 51, 76 (number), 76, 106 (number), 106, 141 (number), 141, 181 (number), 181, 226 (number), 226, 276 (number), 276, 331 (number), 331, 391 (number), 391, 456 (number), 456, 526 (number), 526, 601 (number), 601, 681, 766, 856, 951, 1051, 1156, 1266, 1381, 1501, 1626, 1756, 1891, 2031, 2176, 2326, 2481, 2641, 2806, 2976 . Properties *The parity of centered pentagonal numbers follows the pattern odd-even-even-odd, and in base 10 the units follow the pattern 1-6-6-1. *Centered pentagonal numbers follow the following recurrence relations: :P_=P_+5n , P_0=1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
181 (number)
181 (one hundred ndeighty-one) is the natural number following 180 and preceding 182. In mathematics 181 is prime, and a palindromic, strobogrammatic, and dihedral number in decimal. 181 is a Chen prime. 181 is a twin prime with 179, equal to the sum of ''five'' consecutive prime numbers: 29 + 31 + 37 + 41 + 43. 181 is the difference of two consecutive square numbers 912 – 902, as well as the sum of two consecutive squares: 92 + 102. As a '' centered polygonal number'', 181 is: 181 is also a centered ( hexagram) '' star number'', as in the game of Chinese checkers. Specifically, 181 is the 42nd prime number and ''16th'' ''full reptend prime'' in decimal, where multiples of its reciprocal \tfrac inside a prime reciprocal magic square repeat 180 digits with a magic sum M of 810; this value is one less than 811, the 141st prime number and ''49th'' full reptend prime (or equivalently ''long prime'') in decimal whose reciprocal repeats 810 digits. Whil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polygonal Number
In mathematics, a polygonal number is a Integer, number that counts dots arranged in the shape of a regular polygon. These are one type of 2-dimensional figurate numbers. Polygonal numbers were first studied during the 6th century BC by the Ancient Greeks, who investigated and discussed properties of Pronic number, oblong, Triangular Number, triangular, and Square number, square numbers. Definition and examples The number 10 for example, can be arranged as a triangle (see triangular number): : But 10 cannot be arranged as a square (geometry), square. The number 9, on the other hand, can be (see square number): : Some numbers, like 36, can be arranged both as a square and as a triangle (see square triangular number): : By convention, 1 is the first polygonal number for any number of sides. The rule for enlarging the polygon to the next size is to extend two adjacent arms by one point and to then add the required extra sides between those points. In the following diagrams, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pentagonal Number
A pentagonal number is a figurate number that extends the concept of triangular number, triangular and square numbers to the pentagon, but, unlike the first two, the patterns involved in the construction of pentagonal numbers are not rotational symmetry, rotationally symmetrical. The ''n''th pentagonal number ''pn'' is the number of ''distinct'' dots in a pattern of dots consisting of the ''outlines'' of regular pentagons with sides up to n dots, when the pentagons are overlaid so that they share one vertex (geometry), vertex. For instance, the third one is formed from outlines comprising 1, 5 and 10 dots, but the 1, and 3 of the 5, coincide with 3 of the 10 – leaving 12 distinct dots, 10 in the form of a pentagon, and 2 inside. ''p''n is given by the formula: :p_n = =\binom+3\binom for ''n'' ≥ 1. The first few pentagonal numbers are: 1 (number), 1, 5 (number), 5, 12 (number), 12, 22 (number), 22, 35 (number), 35, 51 (number), 51, 70 (number), 70, 92 (number), 92, 117 (nu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triangular Number
A triangular number or triangle number counts objects arranged in an equilateral triangle. Triangular numbers are a type of figurate number, other examples being square numbers and cube numbers. The th triangular number is the number of dots in the triangular arrangement with dots on each side, and is equal to the sum of the natural numbers from 1 to . The first 100 terms sequence of triangular numbers, starting with the 0th triangular number, are Formula The triangular numbers are given by the following explicit formulas: where \textstyle is notation for a binomial coefficient. It represents the number of distinct pairs that can be selected from objects, and it is read aloud as " plus one choose two". The fact that the nth triangular number equals n(n+1)/2 can be illustrated using a visual proof. For every triangular number T_n, imagine a "half-rectangle" arrangement of objects corresponding to the triangular number, as in the figure below. Copying this arrangement ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Recurrence Relations
In mathematics, a recurrence relation is an equation according to which the nth term of a sequence of numbers is equal to some combination of the previous terms. Often, only k previous terms of the sequence appear in the equation, for a parameter k that is independent of n; this number k is called the ''order'' of the relation. If the values of the first k numbers in the sequence have been given, the rest of the sequence can be calculated by repeatedly applying the equation. In ''linear recurrences'', the th term is equated to a linear function of the k previous terms. A famous example is the recurrence for the Fibonacci numbers, F_n=F_+F_ where the order k is two and the linear function merely adds the two previous terms. This example is a linear recurrence with constant coefficients, because the coefficients of the linear function (1 and 1) are constants that do not depend on n. For these recurrences, one can express the general term of the sequence as a closed-form expression o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
601 (number)
600 (six hundred) is the natural number following 599 and preceding 601. Mathematical properties Six hundred is a composite number, an abundant number, a pronic number, a Harshad number and a largely composite number. Credit and cars * In the United States, a credit score of 600 or below is considered poor, limiting available credit at a normal interest rate * NASCAR runs 600 advertised miles in the Coca-Cola 600, its longest race * The Fiat 600 is a car, the SEAT 600 its Spanish version Integers from 601 to 699 600s * 601 = prime number, centered pentagonal number * 602 = 2 × 7 × 43, nontotient, number of cubes of edge length 1 required to make a hollow cube of edge length 11, area code for Phoenix, AZ along with 480 and 623 * 603 = 32 × 67, Harshad number, Riordan number, area code for New Hampshire * 604 = 22 × 151, nontotient, totient sum for first 44 integers, area code for southwestern British Columbia (Lower Mainland, Fraser Valley, Sunshine Coast and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
526 (number)
500 (five hundred) is the natural number following 499 and preceding 501. Mathematical properties 500 = 22 × 53. It is an Achilles number and a Harshad number, meaning it is divisible by the sum of its digits. It is the number of planar partitions of 10. Other fields Five hundred is also *the number that many NASCAR races often use at the end of their race names (e.g., Daytona 500), to denote the length of the race (in miles, kilometers or laps). *the longest advertised distance (in miles) of the IndyCar Series and its premier race, the Indianapolis 500. Slang names * Monkey (UK slang for £500; US slang for $500) Integers from 501 to 599 500s 501 501 = 3 × 167. It is: * the sum of the first 18 primes (a term of the sequence ). * palindromic in bases 9 (6169) and 20 (15120). 502 * 502 = 2 × 251 * vertically symmetric number 503 503 is: * a prime number. * a safe prime. * the sum of three consecutive primes (163 + 167 + 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
456 (number)
400 (four hundred) is the natural number following 399 and preceding 401. Mathematical properties A circle is divided into 400 grads. Integers from 401 to 499 400s 401 401 is a prime number, tetranacci number, Chen prime, prime index prime * Eisenstein prime with no imaginary part * Sum of seven consecutive primes (43 + 47 + 53 + 59 + 61 + 67 + 71) * Sum of nine consecutive primes (29 + 31 + 37 + 41 + 43 + 47 + 53 + 59 + 61) * Mertens function returns 0, * Member of the Mian–Chowla sequence. 402 402 = 2 × 3 × 67, sphenic number, nontotient, Harshad number, number of graphs with 8 nodes and 9 edges * HTTP status code for "Payment Required". *The area code for Nebraska. 403 403 = 13 × 31, heptagonal number, Mertens function returns 0. * First number that is the product of an emirp pair. * HTTP 403, the status code for "Forbidden" * Also in the name of a retirement plan in the United States, 403(b). * The area code for southern Alberta. 404 4 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
391 (number)
300 (three hundred) is the natural number following 299 and preceding 301. In Mathematics 300 is a composite number and the 24th triangular number. It is also a second hexagonal number. Integers from 301 to 399 300s 301 302 303 304 305 306 307 308 309 310s 310 311 312 313 314 315 315 = 32 × 5 × 7 = D_ \!, rencontres number, highly composite odd number, having 12 divisors. It is a Harshad number, as it is divisible by the sum of its digits. It is a Zuckerman number, as it is divisible by the product of its digits. 316 316 = 22 × 79, a centered triangular number and a centered heptagonal number. 317 317 is a prime number, Eisenstein prime with no imaginary part, Chen prime, one of the rare primes to be both right and left-truncatable, and a strictly non-palindromic number. 317 is the exponent (and number of ones) in the fourth base-10 repunit prime. 318 319 319 = ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
331 (number)
300 (three hundred) is the natural number following 299 and preceding 301. In Mathematics 300 is a composite number and the 24th triangular number. It is also a second hexagonal number. Integers from 301 to 399 300s 301 302 303 304 305 306 307 308 309 310s 310 311 312 313 314 315 315 = 32 × 5 × 7 = D_ \!, rencontres number, highly composite odd number, having 12 divisors. It is a Harshad number, as it is divisible by the sum of its digits. It is a Zuckerman number, as it is divisible by the product of its digits. 316 316 = 22 × 79, a centered triangular number and a centered heptagonal number. 317 317 is a prime number, Eisenstein prime with no imaginary part, Chen prime, one of the rare primes to be both right and left-truncatable, and a strictly non-palindromic number. 317 is the exponent (and number of ones) in the fourth base-10 repunit prime. 318 319 319 = 11 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
276 (number)
276 (two hundred ndseventy-six) is the natural number following 275 and preceding 277. In mathematics 276 is the sum of 3 consecutive fifth powers (276 = 15 + 25 + 35). As a figurate number it is the 23rd triangular number, a hexagonal number, and a centered pentagonal number, the third number after 1 and 6 to have this combination of properties. 276 is the first triangular number that can be arrived at in three ways by adding pairs of triangular numbers together. This sequence, dubbed 'Triple Triangle-Pair Numbers' is the sequence of integers: 276, 406, 666, ... 276 is the size of the largest set of equiangular lines in 23 dimensions. The maximal set of such lines, derived from the Leech lattice, provides the highest dimension in which the "Gerzon bound" of \binom is known to be attained; its symmetry group is the third Conway group, Co3. 276 is the smallest number for which it is not known if the corresponding aliquot sequence either terminates or ends in a repeating cyc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
