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A009082 Expansion of e.g.f. cos(tan(x)/cosh(x)), even terms only. 1
1, -1, 5, -157, 3817, -257049, 15886125, -1844058101, 218349214545, -38729647296945, 7468216325125589, -1882371895493492429, 533348579359954590009, -181834605583994802568393 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..239

MATHEMATICA

With[{nmax = 60}, CoefficientList[Series[Cos[Tan[x]/Cosh[x]], {x, 0, nmax}], x]*Range[0, nmax]!][[1 ;; -1 ;; 2]] (* G. C. Greubel, Jul 24 2018 *)

PROG

(PARI) x='x+O('x^60); v=Vec(serlaplace(cos(tan(x)/cosh(x)))); vector(#v\2, n, v[2*n-1]) \\ G. C. Greubel, Jul 24 2018

CROSSREFS

Sequence in context: A305487 A305087 A316738 * A156134 A183263 A155208

Adjacent sequences:  A009079 A009080 A009081 * A009083 A009084 A009085

KEYWORD

sign

AUTHOR

R. H. Hardin

EXTENSIONS

Extended with signs by Olivier Gérard, Mar 15 1997

STATUS

approved

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Last modified January 28 00:32 EST 2020. Contains 331313 sequences. (Running on oeis4.)