A327034 Expansion of e.g.f. exp(x) / (2 - cosh(x)).

1, 1, 2, 4, 14, 46, 242, 1114, 7814, 46246, 405482, 2933074, 30860414, 263817646, 3238391522, 31943268634, 448122565814, 5009616448246, 79063212894362, 987840438629794, 17322647732052014, 239217148602642046, 4614370558369770002, 69790939492563608554

Offset

0,3

Links

Table of n, a(n) for n=0..23.

Formula

a(0) = 1; a(n) = Sum_{k=1..n} (-1)^k * binomial(n,k) * (2^(k - 1) - 2) * a(n-k).

a(n) ~ n! * (7 + 4*sqrt(3) + (-1)^n) / ((3+2*sqrt(3)) * (log(2+sqrt(3)))^(n+1)). - Vaclav Kotesovec, Dec 03 2019

Mathematica

nmax = 23; CoefficientList[Series[Exp[x]/(2 - Cosh[x]), {x, 0, nmax}], x] Range[0, nmax]!

Crossrefs

Cf. A081557, A094088, A330046.

Sequence in context: A005437 A214267 A266695 * A263741 A263742 A263743

Adjacent sequences: A327031 A327032 A327033 * A327035 A327036 A327037

Keyword

nonn

Author

Ilya Gutkovskiy, Nov 28 2019

Status

approved