A009517 - OEIS

A009517

Expansion of sin(tan(x)/cosh(x)).

1, -2, 32, -688, 29952, -1922560, 160364544, -19815696384, 2743045259264, -538516252917760, 112957538226929664, -31810392390007521280, 9466977656209217159168, -3592556624975295837896704

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OFFSET

1,2

LINKS

Table of n, a(n) for n=1..14.

MATHEMATICA

With[{nn=30}, Take[CoefficientList[Series[Sin[Tan[x]/Cosh[x]], {x, 0, nn}], x]Range[0, nn-1]!, {2, -1, 2}]] (* Harvey P. Dale, May 08 2012 *)

CROSSREFS

Sequence in context: A068110 A304860 A198599 * A354382 A202408 A069182

Adjacent sequences: A009514 A009515 A009516 * A009518 A009519 A009520

KEYWORD

sign

AUTHOR

R. H. Hardin

EXTENSIONS

Extended with signs by Olivier Gérard, Mar 15 1997

STATUS

approved