149 (one hundred ndforty-nine) is the

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 n ...

between

148 148 may refer to: *148 (number), a natural number *AD 148, a year in the 2nd century AD *148 BC, a year in the 2nd century BC *148 (album), an album by C418 *148 (Meiktila) Battery Royal Artillery *148 (New Jersey bus) 148 may refer to: *148 (numb ...

and

150 150 may refer to: *150 (number), a natural number *AD 150, a year in the 2nd century AD *150 BC, a year in the 2nd century BC *150 Regiment RLC *Combined Task Force 150 See also * List of highways numbered 150 The following highways are numbered ...

In mathematics

149 is a

prime number A prime number (or a prime) is a natural number greater than 1 that is not a product of two smaller natural numbers. A natural number greater than 1 that is not prime is called a composite number. For example, 5 is prime because the only ways ...

, the first prime whose difference from the previous prime is exactly 10, an

emirp An emirp (''prime'' spelled backwards) is a prime number that results in a different prime when its decimal digits are reversed. This definition excludes the related palindromic primes. The term ''reversible prime'' is used to mean the same as ...

, and an

irregular prime In number theory, a regular prime is a special kind of prime number, defined by Ernst Kummer in 1850 to prove certain cases of Fermat's Last Theorem. Regular primes may be defined via the divisibility of either class numbers or of Bernoulli num ...

. After 1 and 127, it is the third smallest de Polignac number, an odd number that cannot be represented as a prime plus a

power of two A power of two is a number of the form where is an integer, that is, the result of exponentiation with number two as the base and integer as the exponent. In a context where only integers are considered, is restricted to non-negative ...

. More strongly, after 1, it is the second smallest number that is not a sum of two

prime power In mathematics, a prime power is a positive integer which is a positive integer power of a single prime number. For example: , and are prime powers, while , and are not. The sequence of prime powers begins: 2, 3, 4, 5, 7, 8, 9, 11, 13, 16, 17 ...

s. It is a

tribonacci number In mathematics, the Fibonacci numbers form a sequence defined recursion, recursively by: :F_n = \begin 0 & n = 0 \\ 1 & n = 1 \\ F_ + F_ & n > 1 \end That is, after two starting values, each number is the sum of the two preceding numbers. The Fibo ...

, being the sum of the three preceding terms, 24, 44, 81. There are exactly 149 integer points in a closed circular disk of radius 7, and exactly 149 ways of placing six queens (the maximum possible) on a 5 × 5 chess board so that each queen attacks exactly one other. The

barycentric subdivision In mathematics, the barycentric subdivision is a standard way to subdivide a given simplex into smaller ones. Its extension on simplicial complexes is a canonical method to refine them. Therefore, the barycentric subdivision is an important tool i ...

of a

tetrahedron In geometry, a tetrahedron (plural: tetrahedra or tetrahedrons), also known as a triangular pyramid, is a polyhedron composed of four triangular faces, six straight edges, and four vertex corners. The tetrahedron is the simplest of all the o ...

produces an

abstract simplicial complex In combinatorics, an abstract simplicial complex (ASC), often called an abstract complex or just a complex, is a family of sets that is closed under taking subsets, i.e., every subset of a set in the family is also in the family. It is a purely c ...

with exactly 149 simplices.

References

External links

{{DEFAULTSORT:149 (Number) Integers