A009051 - OEIS

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A009051

Expansion of e.g.f. cos(sin(x)/cosh(x)), even powers only.

1, -1, 17, -457, 19777, -1305489, 122670033, -15462740633, 2502900454401, -504155298072609, 123438576028985873, -36064963500185608553, 12385279694301347665473, -4936243039568368083279793, 2258619438301840395444067537, -1175352020113183347337766918201

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

OFFSET

0,3

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..238

MATHEMATICA

With[{nn=30}, Take[CoefficientList[Series[Cos[Sin[x]/Cosh[x]], {x, 0, nn}], x] Range[ 0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Mar 27 2013 *)

PROG

(PARI) x='x+O('x^60); v=Vec(serlaplace(cos(sin(x)/cosh(x)))); vector(#v\2, n, v[2*n-1]) \\ G. C. Greubel, Jul 23 2018

CROSSREFS

Sequence in context: A271438 A371488 A122430 * A035276 A196484 A196717

Adjacent sequences: A009048 A009049 A009050 * A009052 A009053 A009054