A107096 G.f. A(x) satisfies: A(x)^2 = x*G(x) where G(G(x)) = (1+x)^2*G(x) and G(x) is the g.f. of A107095.

0, 1, 1, -2, 11, -88, 869, -9876, 124473, -1701630, 24870695, -384795184, 6257294780, -106377162620, 1882982975521, -34593496243070, 657935674477431, -12927331575084846, 261951066040220637, -5466177185459699916, 117315664923801661485, -2586804284853871362408

Offset

0,4

Links

Table of n, a(n) for n=0..21.

Formula

G.f. satisfies: A(x)^2 = x*A( A(x)^2/x )/(1+x).

G.f. satisfies: A(x) = x + x*Series_Reversion( A(x)^2/x ). - Paul D. Hanna, Mar 15 2010

Prog

(PARI) {a(n)=local(A, B, F); if(n<1, 0, F=x+2*x^2+x*O(x^n); A=F; for(j=0, n, for(i=0, j, B=serreverse(A); A=(A+subst(B, x, A*(1+x)^2))/2); A=round(A)); polcoeff(sqrt(x*A), n, x))}
(PARI) {a(n)=local(A=1+x+x*O(x^n)); for(i=1, n, A=1+serreverse(x*subst(A^2, x, x+x*O(x^n)))); polcoeff(x*A, n)} \\ Paul D. Hanna, Mar 15 2010

Crossrefs

Cf. A107095.

Sequence in context: A305537 A036076 A047797 * A361599 A138739 A216831

Adjacent sequences: A107093 A107094 A107095 * A107097 A107098 A107099

Keyword

sign

Author

Paul D. Hanna, May 12 2005

Status

approved