A009150 - OEIS

%I #18 Apr 01 2017 11:49:22

%S 1,0,12,-240,5712,-266880,18566592,-1488963840,141287377152,

%T -16736203345920,2412897423240192,-402658140395089920,

%U 76287123858146906112,-16430034737688309104640,4011640516519571786022912,-1097783068806961397511290880

%N Expansion of e.g.f. cosh(sin(x)^2) (even coefficients).

%H Alois P. Heinz, <a href="/A009150/b009150.txt">Table of n, a(n) for n = 0..100</a>

%F a(n) = (2*n)! * [x^(2*n)] cosh(sin(x)^2).

%p a:= n-> coeff(series(cosh(sin(x)^2), x, 2*n+1), x, 2*n)*(2*n)!:

%p seq ( a(n), n=0..20);  # _Alois P. Heinz_, Aug 15 2012

%t With[{nn=30},Take[CoefficientList[Series[Cosh[Sin[x]^2],{x,0,nn}],x]Range[0,nn]!,{1,-1,2}]] (* _Harvey P. Dale_, Aug 15 2012 *)

%K sign

%O 0,3

%A _R. H. Hardin_

%E Extended with signs by _Olivier Gérard_, Mar 15 1997

%E More terms from, and definition clarified by, _Harvey P. Dale_, Aug 15 2012