151848

Appears in sequences

• Expansion of e.g.f. cosh(exp(x)*x).at n=9A009121
• Number of ways to color vertices of a heptagon using <= n colors, allowing rotations and reflections.at n=8A060532
• Values of n such that n^a-+a are primes, a=11.at n=21A155023
• Consider necklaces with n beads, each of one of four colors (say C1, C2, C3, C4), where the n segments of cord between the beads are each colored red or green; a(n) is the number of different necklaces under the action of the dihedral group D_{2n}.at n=7A161222
• For n >= 3, draw a regular n-sided polygon and its n*(n-3)/2 diagonals, so there are n*(n-1)/2 lines; a(n) is the number of ways to choose a subset of these lines (subsets differing by a rotation or reflection are regarded as identical). a(1)=1, a(2)=2 by convention.at n=6A191563
• Number n such that Fibonacci(n) is divisible by n, n + 1 and n - 1.at n=22A221018
• Denominator of Sum_{k=1..n} 1/(k(k+1)(k+2)(k+3)) = Sum_{k=1..n} 1/Pochhammer(k,4).at n=35A230340
• Triangle read by rows: T(n,k) is the number of unlabeled weakly connected acyclic digraphs with n arcs and k vertices, n >= 0, k = 1..n+1.at n=62A350450
• Numbers that are the concatenation of two palindromes and that have exactly two palindromic factors, all with the same number of decimal digits.at n=28A355148
• Table read by downward antidiagonals: T(n,k) is the number of tilings of the n X k cylinder up to horizontal reflections by two tiles that are each fixed under horizontal reflection.at n=42A368258