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A241999
G.f. satisfies: A(x)^2 = x + A(x*A(x)^7).
6
1, 1, 6, 135, 4811, 229670, 13511540, 936653101, 74430448182, 6655256746640, 660714896623941, 72089721075875610, 8574673889180457825, 1104434190128518376048, 153171642055215265173031, 22761836879580561483967360, 3608810191272206965533932200
OFFSET
0,3
COMMENTS
In general, if g.f. satisfies: A(x)^2 = x + A(x*A(x)^q), q > 1, then a(n) ~ c(q) * q^n * n^(n - 1/q + (1/2 - 3/(2*q))*log(2)) / (exp(n) * log(2)^n), where c(q) is a constant independent on n.
LINKS
FORMULA
a(n) ~ c * 7^n * n^(n - 1/7 + 2/7*log(2)) / (exp(n) * log(2)^n), where c = 0.1428317047130699...
PROG
(PARI) {a(n)=local(A=[1, 1], Ax); for(i=1, n, A=concat(A, 0); Ax=Ser(A);
A[#A]=Vec(1+subst(Ax, x, x*Ax^7) - Ax^2)[#A]); A[n+1]}
for(n=0, 30, print1(a(n), ", "))
CROSSREFS
Cf. A240996 (q=2), A240999 (q=3), A241996 (q=4), A241997 (q=5), A241998 (q=6).
Sequence in context: A050281 A096756 A356505 * A333005 A013299 A013295
KEYWORD
nonn
AUTHOR
Vaclav Kotesovec, Aug 11 2014
STATUS
approved