A107701 Self-COMPOSE of A107700; thus g.f. A(x) = G(G(x)) = x + 2*G(x)^2, where G(x) is the g.f. of A107700.
1, 2, 4, 6, 4, -6, -8, 44, 52, -520, -580, 8628, 9312, -188326, -199136, 5210560, 5435860, -178308938, -184306176, 7409693156, 7608810060, -368330924160, -376418726640, 21620184591972, 22015468707328, -1481473941622200, -1504385498284500, 117304374434860032
Offset: 1
Keywords
Programs
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PARI
{a(n)=local(A,B,F);A=x+x^2+x*O(x^n);if(n<1,0, for(i=0,n,F=x+2*A^2;B=serreverse(A);A=(A+subst(B,x,F))/2); polcoeff(x+2*A^2,n,x))}
Formula
G.f. satisfies: A(-A(-x)) = x.