

A009554


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


1



1, 2, 36, 944, 45136, 3263072, 334656960, 46199442176, 8260388524288, 1857027989588480, 512693973356712960, 170529221696594702336, 67257392621575577522176, 31036094843772953163063296
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,2


LINKS

G. C. Greubel, Table of n, a(n) for n = 1..233


FORMULA

a(n) ~ (2*n1)! * 4 * sin(arcsinh(Pi/2)) / (sqrt(4+Pi^2) * (arcsinh(Pi/2))^(2*n)).  Vaclav Kotesovec, Jan 23 2015


MATHEMATICA

With[{nn=30}, Take[CoefficientList[Series[Sin[x]/Cos[Sinh[x]], {x, 0, nn}], x]Range[0, nn1]!, {2, 1, 2}]] (* Harvey P. Dale, Jan 19 2012 *)


PROG

(PARI) x='x+O('x^50); v=Vec(serlaplace(sin(x)/cos(sinh(x)))); vector((#v1)\2 , n, v[2*n1]) // G. C. Greubel, Jan 20 2018


CROSSREFS

Sequence in context: A166473 A279575 A009539 * A209036 A305596 A210899
Adjacent sequences: A009551 A009552 A009553 * A009555 A009556 A009557


KEYWORD

nonn


AUTHOR

R. H. Hardin


EXTENSIONS

Extended and signs tested by Olivier Gérard, Mar 15 1997
Offset corrected by Vaclav Kotesovec, Jan 23 2015


STATUS

approved



