A009592 - OEIS

A009592

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

1, 3, 17, 315, 9505, 413523, 26287601, 2238416523, 246589091137, 34186190864163, 5819027995038161, 1193323792251385179, 290182644485513596513, 82559758988564841189747

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OFFSET

1,2

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..241

FORMULA

a(n) ~ (2*n-1)! * sinh(1) * 2^(2*n+1) / Pi^(2*n). - Vaclav Kotesovec, Jan 23 2015

MATHEMATICA

Sinh[ Sin[ x ] ]/Cos[ x ] (* Odd Part *)

nn = 20; Table[(CoefficientList[Series[Sec[x]*Sinh[Sin[x]], {x, 0, 2*nn+1}], x] * Range[0, 2*nn+1]!)[[n]], {n, 2, 2*nn, 2}] (* Vaclav Kotesovec, Jan 23 2015 *)

PROG

(PARI) x='x+O('x^30); v=Vec(serlaplace(sinh(sin(x))/cos(x))); vector((#v-1)\2 , n, v[2*n-1]) \\ G. C. Greubel, Jan 30 2018

CROSSREFS

Sequence in context: A062622 A271609 A290806 * A051294 A192556 A144033

Adjacent sequences: A009589 A009590 A009591 * A009593 A009594 A009595

KEYWORD

nonn

AUTHOR

R. H. Hardin

EXTENSIONS

Extended and signs tested by Olivier Gérard, Mar 15 1997

Changed offset to 1 by Vaclav Kotesovec, Jan 23 2015

STATUS

approved