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%I #14 Jan 27 2018 18:21:05
%S 1,1,0,-7,-24,61,1200,4493,-48384,-781319,-1804800,85444193,
%T 1210361856,-1847527499,-288162201600,-3428482320907,33720680349696,
%U 1637781983297521,14158399925452800,-431041350297034807,-14236987086964260864
%N E.g.f. 1/(1 - sin(x) + sin(x)^2).
%F a(n) = 2*sum(m=1..n, sum(j=0..(n-m)/2, (binomial(m,n-m-2*j)*sum(i=0..(n-2*j)/2, (2*i+2*j-n)^n*binomial(n-2*j,i)*(-1)^(m-j-i)))/2^(n-2*j))), n>0, a(0)=1. - _Vladimir Kruchinin_, Jun 08 2011
%t With[{nn=20},CoefficientList[Series[1/(1-Sin[x]+Sin[x]^2),{x,0,nn}],x] Range[0,nn]!] (* _Harvey P. Dale_, Mar 20 2015 *)
%o (Maxima)
%o a(n):=2*sum(sum((binomial(m,n-m-2*j)*sum((2*i+2*j-n)^n*binomial(n-2*j,i)*(-1)^(m-j-i),i,0,(n-2*j)/2))/2^(n-2*j),j,0,(n-m)/2),m,1,n); /* _Vladimir Kruchinin_, Jun 08 2011 */
%Y Cf. A029585.
%K sign
%O 0,4
%A _N. J. A. Sloane_
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