A009274 - OEIS

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A009274

E.g.f.: exp(tanh(x)/cos(x)).

1, 1, 1, 2, 5, 32, 157, 688, 3817, 29952, 257049, 1922560, 15886125, 160364544, 1844058101, 19815696384, 218349214545, 2743045259264, 38729647296945, 538516252917760, 7468216325125589, 112957538226929664, 1882371895493492429

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,4

LINKS

Table of n, a(n) for n=0..22.

MATHEMATICA

With[{nn=30}, CoefficientList[Series[Exp[Tanh[x]/Cos[x]], {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Aug 25 2012 *)

PROG

(PARI) for(n=1, #t=Vec(exp(tanh(x)/cos(x))), print1((n-1)!*t[n]", ")) \\ - M. F. Hasler, Aug 25 2012

CROSSREFS

Sequence in context: A261045 A145656 A221680 * A019036 A005636 A067299

Adjacent sequences: A009271 A009272 A009273 * A009275 A009276 A009277

KEYWORD

nonn

AUTHOR

R. H. Hardin

EXTENSIONS

Extended and formatted by Olivier Gérard, Mar 15 1997

Definition clarified by Harvey P. Dale, Aug 25 2012

STATUS

approved