A024230 Expansion of e.g.f. sin(x)*sin(sinh(x))/2 (even powers only).

0, 1, -2, -21, -4, 2677, 49978, 11487, -36275464, -1538399639, -22119645578, 2006421812307, 213180133008116, 10489769063373277, -27722182352718926, -68871270400638150585, -8464386105916692002320, -535985815068329924418863

Offset

0,3

Links

Table of n, a(n) for n=0..17.

Formula

a(n) = A009547(n)/2. - R. J. Mathar, Jan 12 2025

Example

sin(x)*sin(sinh(x)) /2 = 0*x^0/0! + 1*x^2/2! -2*x^4/4! -21*x^6/6! -4*x^8/8!... - R. J. Mathar, Jan 12 2025

Mathematica

With[{nn=40}, Take[CoefficientList[Series[Sin[x]*Sin[Sinh[x]]/2, {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Dec 05 2015 *)

Crossrefs

Cf. A009547.

Sequence in context: A100980 A360980 A122509 * A358520 A105666 A058261

Adjacent sequences: A024227 A024228 A024229 * A024231 A024232 A024233

Keyword

sign

Author

R. H. Hardin

Extensions

Extended with signs Mar 1997

Prior Mathematica program replaced by Harvey P. Dale, Dec 05 2015

Status

approved