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A009088 Expansion of e.g.f. x*cos(tanh(x)), odd powers only. 1

%I #25 Jul 30 2018 00:39:09

%S 1,-3,45,-1239,54873,-3577739,322495173,-38370542175,5817952885169,

%T -1093812528874387,249472828725529437,-67807763939709678951,

%U 21642089202188444732425,-8010884242566625383028251

%N Expansion of e.g.f. x*cos(tanh(x)), odd powers only.

%H G. C. Greubel, <a href="/A009088/b009088.txt">Table of n, a(n) for n = 0..239</a>

%p seq(coeff(series(factorial(n)*x*cos(tanh(x)), x,n+1),x,n),n=1..30,2); # _Muniru A Asiru_, Jul 25 2018

%t With[{nn=30},Take[CoefficientList[Series[Cos[Tanh[x]]x,{x,0,nn}], x] Range[0,nn-1]!,{2,-1,2}]] (* _Harvey P. Dale_, Nov 01 2011 *)

%o (PARI) x='x+O('x^60); v=Vec(serlaplace(x*cos(tanh(x)))); vector((#v-1)\2,n,v[2*n-1]) \\ _G. C. Greubel_, Jul 25 2018

%K sign

%O 0,2

%A _R. H. Hardin_

%E Extended with signs by _Olivier GĂ©rard_, Mar 15 1997

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Last modified April 25 11:39 EDT 2024. Contains 371969 sequences. (Running on oeis4.)