A234252 a(n) = ((n-1)^(n+1) + (-1)^n*(n+1)^(n-1))/(n^2).

-1, 1, 0, 23, 112, 2637, 28928, 705259, 12021504, 337390073, 7752749056, 252186614847, 7261683740672, 271082082053317, 9359536638984192, 396049017137512403, 15920162462882529280, 754792662169555947633, 34587513064809080815616, 1818644980834260579498343

Offset

1,4

Comments

a(2n) = A233446(n) = ((2n-1)^(2n+1) + (2n+1)^(2n-1))/(2n)^2 = A154682(n)/(2n)^2 for n > 0.

Links

Table of n, a(n) for n=1..20.

Formula

a(n) = ((n-1)^(n+1) + (-1)^n*(n+1)^(n-1))/(n^2).

Mathematica

Table[((m-1)^(m+1)+(-1)^m*(m+1)^(m-1))/(m^2), {m, 1, 20}]

Prog

(PARI) a(n) = ((n-1)^(n+1) + (-1)^n*(n+1)^(n-1))/n^2; \\ Michel Marcus, Jun 06 2021

Crossrefs

Cf. A154682, A233446.

Sequence in context: A356877 A260986 A071634 * A101804 A142324 A337425

Adjacent sequences: A234249 A234250 A234251 * A234253 A234254 A234255

Keyword

sign

Author

Alexander Adamchuk, Dec 22 2013

Status

approved