A009568 Expansion of e.g.f.: sinh(log(1+sinh(x))).

0, 1, -1, 4, -16, 91, -616, 4894, -44416, 453541, -5145856, 64222984, -874402816, 12897183391, -204862698496, 3486535686274, -63292764553216, 1220795601029641, -24931903045697536, 537463528325234764, -12196043454064623616, 290588368323926512291, -7253387436695186046976

Offset: 0

Author

R. H. Hardin

Keywords

• sign
• easy

Links

• G. C. Greubel, Table of n, a(n) for n = 0..438

Programs

Mathematica

With[{nn=20},CoefficientList[Series[Sinh[Log[1+Sinh[x]]],{x,0,nn}],x] Range[0,nn]!] (* Harvey P. Dale, Dec 08 2017 *)

PARI

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

Formula

a(2*n) = A006154(2*n)/2, n>0. - Ralf Stephan, Apr 29 2004

Extensions

Extended with signs by Olivier Gérard, Mar 15 1997

Prior Mathematica program replaced and definition clarified by Harvey P. Dale, Dec 08 2017

Terms a(20) to a(22) added by G. C. Greubel, Jan 21 2018