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245 (number)
245 (two hundred ndforty-five) is the natural number following 244 and preceding 246. In mathematics 245 is: *a composite number. *a stella octangula number. *palindromic in bases 34 (7734) and 48 (5548) *a Harshad number in bases 7, 9, 11, 15, 31, 35, 36 (and 14 other bases). *the aliquot sum of any of these numbers: 723, 1195, 2563, 3859, *part of the 97-aliquot tree. 4624, 4893, 2595, 1581, 723, 245, In online public access (library) catalogs In the MARC format for records in online public access (library) catalogs, in which each type of information about a book (or other library material) is identified with a 3-digit number, 245 identifies the title of the item; most library catalog software requires that each record have at least a 245 tag, even if no other information is entered about the item. In other fields * The number of Jewish singers who returned from captivity in Babylon in c. 538 BCE following the rise of Cyrus the Great and the Persian Empire. ''...besides the ... [...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] |
244 (number)
244 (two hundred ndforty-four) is the natural number following 243 and preceding 245. In mathematics 244 is: *the sum of two nonzero fifth powers (). *palindromic in bases 3 (1000013), 11 (20211), 60 (4460), 121 (22121), 243 (11243). *a Harshad number in bases 3, 9, 11, 61, 62, 81, 121, 122, 123 and 184. *the second anti-perfect number, meaning that reversing the digits of the proper divisors of 244 and adding the results gives 244 back again. *part of the sequence 1, 2, 4, 8, 61, 221, 244, ... in which each number is formed by reversing the digits of the double of the previous number. *the number of non-isomorphic set-systems of weight 8 In other fields *The years 244 and 244 BC *Dialing code for Angola. *It is considered a lucky number in several areas of the United Arab Emirates; specifically Dubai Dubai (, ; ar, ุฏุจู, translit=Dubayy, , ) is the most populous city in the United Arab Emirates (UAE) and the capital of the Emirate of Dubai, the most populated of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
246 (number)
246 (two hundred ndforty-six) is the natural number following 245 and preceding 247. In mathematics 246 is: *an untouchable number. *palindromic in bases 5 (14415), 9 (3039), 40 (6640), 81 (3381), 122 (22122) and 245 (11245). *a Harshad number in bases 2, 3, 6, 7, 9, 11 (and 15 other bases). *the smallest number N for which it is known that there is an infinite number of prime gaps no larger than N. Also: *The aliquot sequence starting at 246 is: 246, 258, 270, 450, 759, 393, 135, 105, 87, 33, 15, 9, 4, 3, 1, 0. *There are exactly 246 different rooted plane trees with eight nodes, and 246 different necklaces with seven black and seven white beads. In other fields * +246 is the code for international direct dial phone calls to British Indian Ocean Territory (Diego Garcia). * +1246, is the area code assigned to Barbados. * List of highways numbered 246. * 2-4-6, a Whyte notation classification of steam locomotive A steam locomotive is a locomotive that provides the force ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Composite Number
A composite number is a positive integer that can be formed by multiplying two smaller positive integers. Equivalently, it is a positive integer that has at least one divisor other than 1 and itself. Every positive integer is composite, prime, or the unit 1, so the composite numbers are exactly the numbers that are not prime and not a unit. For example, the integer 14 is a composite number because it is the product of the two smaller integers 2 × 7. Likewise, the integers 2 and 3 are not composite numbers because each of them can only be divided by one and itself. The composite numbers up to 150 are: :4, 6, 8, 9, 10, 12, 14, 15, 16, 18, 20, 21, 22, 24, 25, 26, 27, 28, 30, 32, 33, 34, 35, 36, 38, 39, 40, 42, 44, 45, 46, 48, 49, 50, 51, 52, 54, 55, 56, 57, 58, 60, 62, 63, 64, 65, 66, 68, 69, 70, 72, 74, 75, 76, 77, 78, 80, 81, 82, 84, 85, 86, 87, 88, 90, 91, 92, 93, 94, 95, 96, 98, 99, 100, 102, 104, 105, 106, 108, 110, 111, 112, 114, 115, 116, 117, 118, 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stella Octangula Number
In mathematics, a stella octangula number is a figurate number based on the stella octangula, of the form .. The sequence of stella octangula numbers is :0, 1, 14, 51, 124, 245, 426, 679, 1016, 1449, 1990, ... Only two of these numbers are square. Ljunggren's equation There are only two positive square stella octangula numbers, and , corresponding to and respectively.. The elliptic curve describing the square stella octangula numbers, :m^2 = n (2n^2 - 1) may be placed in the equivalent Weierstrass form :x^2 = y^3 - 2y by the change of variables , . Because the two factors and of the square number are relatively prime, they must each be squares themselves, and the second change of variables X=m/\sqrt and Y=\sqrt leads to Ljunggren's equation :X^2 = 2Y^4 - 1 A theorem of Siegel Siegel (also Segal or Segel), is a German and Ashkenazi Jewish surname. it can be traced to 11th century Bavaria and was used by people who made wax seals for or sealed official documents (each su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harshad Number
In mathematics, a harshad number (or Niven number) in a given number base is an integer that is divisible by the sum of its digits when written in that base. Harshad numbers in base are also known as -harshad (or -Niven) numbers. Harshad numbers were defined by D. R. Kaprekar, a mathematician from India. The word "harshad" comes from the Sanskrit ' (joy) + ' (give), meaning joy-giver. The term "Niven number" arose from a paper delivered by Ivan M. Niven at a conference on number theory in 1977. Definition Stated mathematically, let be a positive integer with digits when written in base , and let the digits be a_i (i = 0, 1, \ldots, m-1). (It follows that a_i must be either zero or a positive integer up to .) can be expressed as :X=\sum_^ a_i n^i. is a harshad number in base if: :X \equiv 0 \bmod . A number which is a harshad number in every number base is called an all-harshad number, or an all-Niven number. There are only four all-harshad numbers: 1, 2, 4, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MARC Standards
MARC (machine-readable cataloging) standards are a set of digital formats for the description of items catalogued by libraries, such as books, DVDs, and digital resources. Computerized library catalogs and library management software need to structure their catalog records as per an industry-wide standard, which is MARC, so that bibliographic information can be shared freely between computers. The structure of bibliographic records almost universally follows the MARC standard. Other standards work in conjunction with MARC, for example, Anglo-American Cataloguing Rules (AACR)/Resource Description and Access (RDA) provide guidelines on formulating bibliographic data into the MARC record structure, while the International Standard Bibliographic Description (ISBD) provides guidelines for displaying MARC records in a standard, human-readable form. History Working with the Library of Congress, American computer scientist Henriette Avram developed MARC during 1965โ1968 to create reco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Online Public Access Catalog
The online public access catalog (OPAC), now frequently synonymous with '' library catalog'', is an online database of materials held by a library or group of libraries. Online catalogs have largely replaced the analog card catalogs previously used in libraries. History Early online Although a handful of experimental systems existed as early as the 1960s, the first large-scale online catalogs were developed at Ohio State University in 1975 and the Dallas Public Library in 1978. These and other early online catalog systems tended to closely reflect the card catalogs that they were intended to replace. Using a dedicated terminal or telnet client, users could search a handful of pre-coordinate indexes and browse the resulting display in much the same way they had previously navigated the card catalog. Throughout the 1980s, the number and sophistication of online catalogs grew. The first commercial systems appeared, and would by the end of the decade largely replace systems bui ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyrus The Great
Cyrus II of Persia (; peo, ๐ค๐ข๐ฝ๐ข๐ ), commonly known as Cyrus the Great, was the founder of the Achaemenid Empire, the first Persian empire. Schmitt Achaemenid dynasty (i. The clan and dynasty) Under his rule, the empire embraced all of the previous civilized states of the ancient Near East, expanded vastly and eventually conquered most of Western Asia and much of Central Asia. Spanning from the Mediterranean Sea and Hellespont in the west to the Indus River in the east, the empire created by Cyrus was the largest the world had yet seen. At its maximum extent under his successors, the Achaemenid Empire stretched from parts of the Balkans ( Eastern Bulgariaโ Paeonia and Thraceโ Macedonia) and Southeast Europe proper in the west to the Indus Valley in the east. The reign of Cyrus lasted about thirty years; his empire took root with his conquest of the Median Empire followed by the Lydian Empire and eventually the Neo-Babylonian Empire. He also led an expedit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Achaemenid Empire
The Achaemenid Empire or Achaemenian Empire (; peo, ๐ง๐๐, , ), also called the First Persian Empire, was an ancient Iranian empire founded by Cyrus the Great in 550 BC. Based in Western Asia, it was contemporarily the largest empire in history, spanning a total of from the Balkans and Egypt in the west to Central Asia and the Indus Valley in the east. Around the 7th century BC, the region of Persis in the southwestern portion of the Iranian plateau was settled by the Persians. From Persis, Cyrus rose and defeated the Median Empire as well as Lydia and the Neo-Babylonian Empire, marking the formal establishment of a new imperial polity under the Achaemenid dynasty. In the modern era, the Achaemenid Empire has been recognized for its imposition of a successful model of centralized, bureaucratic administration; its multicultural policy; building complex infrastructure, such as road systems and an organized postal system; the use of official languages across ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eric Dolphy
Eric Allan Dolphy Jr. (June 20, 1928 – June 29, 1964) was an American jazz alto saxophonist, bass clarinetist and flautist. On a few occasions, he also played the clarinet and piccolo. Dolphy was one of several multi-instrumentalists to gain prominence in the same era. His use of the bass clarinet helped to establish the instrument within jazz. Dolphy extended the vocabulary and boundaries of the alto saxophone, and was among the earliest significant jazz flute soloists. His improvisational style was characterized by the use of wide intervals, in addition to employing an array of extended techniques to emulate the sounds of human voices and animals. He used melodic lines that were "angular, zigzagging from interval to interval, taking hairpin turns at unexpected junctures, making dramatic leaps from the lower to the upper register." Although Dolphy's work is sometimes classified as free jazz, his compositions and solos were often rooted in conventional (if highly abstracted) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
