OFFSET
0,3
LINKS
Vaclav Kotesovec, Table of n, a(n) for n = 0..250
FORMULA
a(n) ~ c * 6^n * n^(n - 1/6 + 1/4*log(2)) / (exp(n) * log(2)^n), where c = 0.1671159774327212...
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^6) - Ax^2)[#A]); A[n+1]}
for(n=0, 30, print1(a(n), ", "))
CROSSREFS
KEYWORD
nonn
AUTHOR
Vaclav Kotesovec, Aug 11 2014
STATUS
approved