A344217 Expansion of e.g.f. log(1 + (1/(1-x)^4 - 1)/4).

0, 1, 4, 17, 69, 204, -330, -12510, -110250, -42840, 16760520, 332942400, 3258208800, -13239903600, -1299112214400, -28283225770800, -232265443410000, 6756753459456000, 338710300424496000, 7139034325607184000, 19827438602379408000, -4654590583125843360000

Offset: 0

Author

Vaclav Kotesovec, May 12 2021

Keywords

• sign

Crossrefs

Column k=4 of A308497.

Programs

Mathematica

nmax = 25; CoefficientList[Series[Log[1 + (1/(1 - x)^4 - 1)/4], {x, 0, nmax}], x] * Range[0, nmax]!

Formula

a(n) ~ -2*(n-1)! * cos(n*arctan(1/(1 - sqrt(2)*3^(1/4)))) / (1 + 1/sqrt(3) - sqrt(2)/3^(1/4))^(n/2).