A009494 Expansion of e.g.f. sin(sinh(x))/cos(x), odd powers only.

1, 3, 17, 203, 5473, 254067, 16540721, 1419027899, 156472224961, 21673957780323, 3688273509233489, 756324514461534251, 183915828663739402273, 52326057512851162076883, 17220068908254192825659249, 6490500645147038725191540251, 2777808923824765305203681470849

Offset

0,2

Links

Robert Israel, Table of n, a(n) for n = 0..241

Maple

S:=series(sin(sinh(x))/cos(x), x, 51):
seq(coeff(S, x, j)*j!, j=1..50, 2); # Robert Israel, Aug 21 2018

Mathematica

With[{nn=50}, Take[CoefficientList[Series[Sin[Sinh[x]]/Cos[x], {x, 0, nn}], x]Range[0, nn-1]!, {2, -1, 2}]] (* Harvey P. Dale, Dec 04 2012 *)

Prog

(Magma) m:=40; R<x>:=PowerSeriesRing(Rationals(), m); b:=Coefficients(R!(1+Sin(Sinh(x))/Cos(x))); [Factorial(n-1)*b[n]: n in [2..m by 2]]; // Vincenzo Librandi, Aug 22 2018

Crossrefs

Sequence in context: A335343 A133991 A210898 * A267659 A075271 A194925

Adjacent sequences: A009491 A009492 A009493 * A009495 A009496 A009497

Keyword

nonn

Author

R. H. Hardin

Extensions

Extended and signs tested by Olivier Gérard, Mar 15 1997

More terms from Harvey P. Dale, Dec 04 2012

Status

approved