A009201 - OEIS

%I #17 Dec 21 2018 11:49:46

%S 1,1,1,-1,-7,-7,73,335,-687,-12367,-19471,461119,2839561,-15282199,

%T -260138759,-15084017,22560194593,113205762401,-1856685484703,

%U -23353924295169,115492830956953,3999727786726617,5211807618131753,-646193037236457649

%N E.g.f. exp(sin(sin(x))).

%t With[{nn=30},CoefficientList[Series[Exp[Sin[Sin[x]]],{x,0,nn}],x] Range[ 0,nn]!] (* _Harvey P. Dale_, Dec 21 2018 *)

%o (Maxima)

%o a(n):=if n=0 then 1 else sum((sum((4^(j+1)*(sum((i-n/2+j)^(n-2*j+2*k)*(-1)^(i)*binomial(n-2*j, i), i, 0, (n/2-j)))*sum((-n/2+j-k+i)^n*binomial(n-2*j+2*k, i)*(-1)^(j-i), i, 0, (n/2-j+k)))/(n-2*j+2*k)!, k, 0, j))/(n-2*j)!, j, 0, (n-1)/2); /* _Vladimir Kruchinin_, Jun 20 2011 */

%K sign,easy

%O 0,5

%A _R. H. Hardin_

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