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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.
2
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
1,2
FORMULA
G.f. satisfies: A(-A(-x)) = x.
PROG
(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))}
CROSSREFS
Sequence in context: A083220 A085896 A351491 * A293812 A011176 A154542
KEYWORD
sign
AUTHOR
Paul D. Hanna, May 21 2005
STATUS
approved