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A024256
Expansion of log(1+sinh(x)*x)/2.
0
0, 1, -4, 63, -2124, 123125, -10909530, 1370980527, -231929847352, 50819745007593, -14001213054748470, 4737203637126866147, -1930988440489283869716, 933336022674019405298013, -527815626641210525156467474
OFFSET
0,3
FORMULA
E.g.f. of aerated sequence: Sum(n>=0, a(n)*x^(2*n)/(2*n)!) = log(1+sinh(x)*x)/2.
MAPLE
S:= series(log(1+sinh(x)*x)/2, x, 101):
seq(coeff(S, x, 2*j)*(2*j)!, j=0..50); # Robert Israel, Jun 29 2015
MATHEMATICA
With[{nn=40}, Take[CoefficientList[Series[Log[1+Sinh[x]*x]/2, {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Oct 14 2011 *)
CROSSREFS
Cf. A009360.
Sequence in context: A299428 A274392 A237644 * A292394 A351779 A203512
KEYWORD
sign
AUTHOR
EXTENSIONS
Extended with signs Mar 1997
STATUS
approved