115 (one hundred [and] fifteen) is the natural number following 114 and preceding 116.

In mathematics

115 has a square sum of divisors:[1]

There are 115 different rooted trees with exactly eight nodes,[2] 115 inequivalent ways of placing six rooks on a 6 × 6 chess board in such a way that no two of the rooks attack each other,[3] and 115 solutions to the stamp folding problem for a strip of seven stamps.[4]

115 is also a heptagonal pyramidal number.[5] The 115th Woodall number,

is a prime number.[6] 115 is the sum of the first five heptagonal numbers.

See also

References

  1. ^ Sloane, N. J. A. (ed.). "Sequence A006532 (Numbers n such that sum of divisors of n is a square)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  2. ^ Sloane, N. J. A. (ed.). "Sequence A000081 (Number of rooted trees with n nodes (or connected functions with a fixed point))". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  3. ^ Sloane, N. J. A. (ed.). "Sequence A000903 (Number of inequivalent ways of placing n nonattacking rooks on n X n board)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  4. ^ Sloane, N. J. A. (ed.). "Sequence A002369 (Number of ways of folding a strip of n rectangular stamps)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  5. ^ Sloane, N. J. A. (ed.). "Sequence A002413 (Heptagonal (or 7-gonal) pyramidal numbers: n*(n+1)*(5*n-2)/6)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
  6. ^ Sloane, N. J. A. (ed.). "Sequence A002234 (Numbers n such that the Woodall number n*2^n - 1 is prime)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.


Allikas: https://en.wikipedia.org/wiki/115_(number)
No tags for this post.