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178 (number)
178 (one hundred ndseventy-eight) is the natural number following 177 and preceding 179. In mathematics There are 178 biconnected graphs with six vertices, among which one is designated as the root and the rest are unlabeled. There are also 178 median graph In graph theory, a division of mathematics, a median graph is an undirected graph in which every three vertices ''a'', ''b'', and ''c'' have a unique ''median'': a vertex ''m''(''a'',''b'',''c'') that belongs to shortest paths between each pair o ...s on nine vertices. 178 is one of the indexes of the smallest triple of dodecahedral numbers where one is the sum of the other two: the sum of the 46th and the 178th dodecahedral numbers is the 179th. See also * The year 178 AD or 178 BC * List of highways numbered 178 * References {{DEFAULTSORT:178 (Number) Integers ... [...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] |
177 (number)
177 (one hundred ndseventy-seven) is the natural number following 176 and preceding 178. In mathematics It is a Leyland number since . It is a 60-gonal number, and an arithmetic number, since the mean of its divisors ( 1, 3, 59 and 177) is equal to 60, an integer. 177 is a Leonardo number, part of a sequence of numbers closely related to the Fibonacci numbers. In graph enumeration, there are 177 undirected graphs (not necessarily connected) that have seven edges and no isolated vertices, and 177 rooted trees with ten nodes and height at most three. There are 177 ways of re-connecting the (labeled) vertices of a regular octagon into a star polygon that does not use any of the octagon edges. In other fields 177 is the second highest score for a flight of three darts Darts or dart-throwing is a competitive sport in which two or more players bare-handedly throw small sharp-pointed missiles known as darts at a round target known as a dartboard. Points can be scored by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
179 (number)
179 (one hundred ndseventy-nine) is the natural number following 178 and preceding 180. In mathematics 179 is part of the Cunningham chain of prime numbers 89, 179, 359, 719, 1439, 2879, in which each successive number is two times the previous number, plus one. Among Cunningham chains of this length, this one has the smallest numbers. Because 179 is neither the start nor the end of this chain, it is both a safe prime and a Sophie Germain prime. It is also a super-prime number, because it is the 41st smallest prime and 41 is also prime. Since 971 (the digits of 179 reversed) is prime, 179 is an emirp. In other fields Astronomers have suggested that sunspot frequency undergoes a cycle of approximately 179 years in length. See also * AD 179 and 179 BC __NOTOC__ Year 179 BC was a year of the pre-Julian Roman calendar. At the time it was known as the Year of the Consulship of Flaccus and Fulvianus (or, less frequently, year 575 ''Ab urbe condita''). The denomination 179 BC for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biconnected Graph
In graph theory, a biconnected graph is a connected and "nonseparable" graph, meaning that if any one vertex were to be removed, the graph will remain connected. Therefore a biconnected graph has no articulation vertices. The property of being 2-connected is equivalent to biconnectivity, except that the complete graph of two vertices is usually not regarded as 2-connected. This property is especially useful in maintaining a graph with a two-fold redundancy, to prevent disconnection upon the removal of a single edge (or connection). The use of biconnected graphs is very important in the field of networking (see Network flow), because of this property of redundancy. Definition A biconnected undirected graph is a connected graph that is not broken into disconnected pieces by deleting any single vertex (and its incident edges). A biconnected directed graph is one such that for any two vertices ''v'' and ''w'' there are two directed paths from ''v'' to ''w'' which have no vert ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Median Graph
In graph theory, a division of mathematics, a median graph is an undirected graph in which every three vertices ''a'', ''b'', and ''c'' have a unique ''median'': a vertex ''m''(''a'',''b'',''c'') that belongs to shortest paths between each pair of ''a'', ''b'', and ''c''. The concept of median graphs has long been studied, for instance by or (more explicitly) by , but the first paper to call them "median graphs" appears to be . As Chung, Graham, and Saks write, "median graphs arise naturally in the study of ordered sets and discrete distributive lattices, and have an extensive literature".. In phylogenetics, the Buneman graph representing all maximum parsimony Phylogenetic tree, evolutionary trees is a median graph. Median graphs also arise in social choice theory: if a set of alternatives has the structure of a median graph, it is possible to derive in an unambiguous way a majority preference among them. Additional surveys of median graphs are given by , , and . Examples ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dodecahedral Number
A dodecahedral number is a figurate number that represents a dodecahedron. The ''n''th dodecahedral number is given by the formula = The first such numbers are 0, 1, 20, 84, 220, 455, 816, 1330, 2024, 2925, 4060, 5456, 7140, 9139, 11480, … . History The first study of dodecahedral numbers appears to have been by René Descartes, around 1630, in his ''De solidorum elementis''. Prior to Descartes, figurate numbers had been studied by the ancient Greeks and by Johann Faulhaber, but only for polygonal numbers, pyramidal numbers, and cubes. Descartes introduced the study of figurate numbers based on the Platonic solids and some semiregular polyhedra; his work included the dodecahedral numbers. However, ''De solidorum elementis'' was lost, and not rediscovered until 1860. In the meantime, dodecahedral numbers had been studied again by other mathematicians, including Friedrich Wilhelm Marpurg in 1774, Georg Simon Klügel Georg Simon Klügel (August 19, 1739 – August 4, 1812) wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
178 BC
__NOTOC__ Year 178 BC was a year of the pre-Julian Roman calendar. At the time it was known as the Year of the Consulship of Brutus and Vulso (or, less frequently, year 576 '' Ab urbe condita''). The denomination 178 BC for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years. Events By place Roman Republic * In Rome, the praetor Lucius Postumius Albinus celebrates a triumph after conquering the Vaccaei and Lusitani during his time as Roman commander in the province of Hispania Ulterior. Greece * One of Perseus' first acts on becoming king of Macedonia is to renew the treaty between Macedonia and Rome. In the meantime, Perseus builds up the Macedonian army and puts out feelers for creating an alliance with the Greek leagues, with his northern barbarian neighbours, and also with the Seleucid king Seleucus IV. Deaths * Chen Ping, Chinese official and chancellor of the Wes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Highways Numbered 178
The following highways are numbered 178: Canada *Prince Edward Island Route 178 Japan * Japan National Route 178 United States * Interstate 178 (former proposal) * U.S. Route 178 * Alabama State Route 178 * Arkansas Highway 178 * California State Route 178 * Connecticut Route 178 * Georgia State Route 178 * Illinois Route 178 * K-178 (Kansas highway) * Kentucky Route 178 * Louisiana Highway 178 * Maine State Route 178 * Maryland Route 178 * M-178 (Michigan highway) (former) * Mississippi Highway 178 * New Jersey Route 178 (never built) * New York State Route 178 * Pennsylvania Route 178 (former) * Tennessee State Route 178 * Texas State Highway 178 ** Texas State Highway Loop 178 ** Farm to Market Road 178 (Texas) * Utah State Route 178 * Virginia State Route 178 * Wisconsin Highway 178 State Trunk Highway 178 (often called Highway 178, STH-178 or WIS 178) is a state highway in Chippewa County, Wisconsin, United States, that runs north–south roughly along the Ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
