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A127783
G.f. satisfies: A(x) = 1 + x*A(x+x^2)^2.
3
1, 1, 2, 7, 28, 133, 700, 4039, 25160, 167637, 1186482, 8872752, 69810994, 575912978, 4967058182, 44675926159, 418157494016, 4065044047125, 40973402647058, 427535487044903, 4611642948647118, 51354908876927025
OFFSET
0,3
LINKS
PROG
(PARI) {a(n)=local(A=1+x+x*O(x^n)); for(i=0, n, A=1+x*subst(A^2, x, x+x^2)); polcoeff(A, n)}
CROSSREFS
Sequence in context: A252737 A217203 A052319 * A297195 A116539 A266467
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Jan 28 2007
STATUS
approved