A009142 - OEIS

%I #20 Jul 31 2018 02:39:57

%S 1,1,-7,73,-687,-19471,2839561,-260138759,22560194593,-1856685484703,

%T 115492830956953,5211807618131753,-4918276086306813839,

%U 1664523472944706933841,-477486870436056568353623

%N Expansion of e.g.f. cosh(sin(sin(x))), even powers only.

%H G. C. Greubel, <a href="/A009142/b009142.txt">Table of n, a(n) for n = 0..250</a>

%p seq(coeff(series(factorial(n)*cosh(sin(sin(x))), x,n+1),x,n),n=0..30,2); # _Muniru A Asiru_, Jul 31 2018

%t With[{nmax = 60}, CoefficientList[Series[Cosh[Sin[Sin[x]]], {x, 0, nmax}], x]*Range[0, nmax]!][[1 ;; -1 ;; 2]] (* _G. C. Greubel_, Jul 30 2018 *)

%o (PARI) x='x+O('x^60); v=Vec(serlaplace(cosh(sin(sin(x))))); vector(#v\2,n,v[2*n-1]) \\ _G. C. Greubel_, Jul 31 2018

%K sign

%O 0,3

%A _R. H. Hardin_

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