A009576 Expansion of e.g.f. sinh(log(1+x))/cos(x).

0, 1, -1, 6, -18, 115, -615, 4732, -36148, 337797, -3315645, 37027826, -440999526, 5768129783, -80507865347, 1210608394920, -19345811001000, 329208442723465, -5922785067664185, 112578608999452894, -2251115252850724090

Offset

0,4

Links

G. C. Greubel, Table of n, a(n) for n = 0..448

Formula

a(n) ~ n! * (-1)^(n+1) / (2*cos(1)). - Vaclav Kotesovec, Jan 23 2015

Mathematica

CoefficientList[Series[(x*(2 + x)*Sec[x])/(2*(1 + x)), {x, 0, 20}], x] * Range[0, 20]! (* Vaclav Kotesovec, Jan 23 2015 *)
With[{nmax = 50}, CoefficientList[Series[Sinh[Log[1 + x]]/Cos[x], {x, 0, nmax}], x]*Range[0, nmax]!] (* G. C. Greubel, Jan 21 208 *)

Prog

(PARI) x='x+O('x^30); concat([0], Vec(serlaplace(sinh(log(1+x))/cos(x)))) \\ G. C. Greubel, Jan 21 2018

Crossrefs

Sequence in context: A108735 A143556 A007126 * A009580 A125839 A117813

Adjacent sequences: A009573 A009574 A009575 * A009577 A009578 A009579

Keyword

sign,easy

Author

R. H. Hardin

Extensions

Extended with signs by Olivier Gérard, Mar 15 1997

Status

approved