A009600 Expansion of e.g.f. sin(tan(x))*x/2 (even powers only).

1, 56, 5056, -8648704, -7517057024, 82066777604096, 27511745714323456, -8171138983967372345344, 74351622296124892534276096, 3458659437902679786800310910976, -174596051680041185684701426120392704, -1616689111713841897872270552294850822144

Offset

0,2

Links

G. C. Greubel, Table of n, a(n) for n = 0..141

Formula

a(n) = (4*n+2)! * [x^(4*n+2)] sinh(sinh(x)*sin(x))/2.

Mathematica

nmax = 50; coes = CoefficientList[Series[Sinh[Sinh[x]*Sin[x]]/2, {x, 0, 4*nmax + 2}], x]; a[n_] := coes[[4*n + 3]]*(4*n + 2)!; Table[a[n], {n, 0, nmax}] (* G. C. Greubel, Jan 30 2018 *)

Crossrefs

Cf. A012528.

Sequence in context: A271139 A271140 A278324 * A278777 A202565 A213693

Adjacent sequences: A009597 A009598 A009599 * A009601 A009602 A009603

Keyword

sign

Author

R. H. Hardin

Extensions

Extended with signs Mar 1997

Status

approved