OFFSET
0,4
LINKS
Paul D. Hanna, Table of n, a(n) for n = 0..200
FORMULA
a(n) ~ c * n^n / (exp(n) * log(2)^(2*n)), where c = 0.51205951699411... - Vaclav Kotesovec, Aug 11 2021
EXAMPLE
G.f.: A(x) = 1 + x + x^2 + 6*x^3 + 41*x^4 + 381*x^5 + 4387*x^6 + 59961*x^7 + 946119*x^8 + 16901219*x^9 + 336924252*x^10 + 7412401676*x^11 + 178372705409*x^12 + ...
such that
1 = 1/A(x) + x/(A(x) + x)^2 + ((1+x)^2 - 1)^2/(A(x) + (1+x)^2 - 1)^3 + ((1+x)^3 - 1)^3/(A(x) + (1+x)^3 - 1)^4 + ((1+x)^4 - 1)^4/(A(x) + (1+x)^4 - 1)^5 + ((1+x)^5 - 1)^5/(A(x) + (1+x)^5 - 1)^6 + ((1+x)^2 - 1)^6/(A(x) + (1+x)^6 - 1)^7 + ...
PROG
(PARI) {a(n) = my(A=[1], X=x+x*O(x^n)); for(i=1, n, A=concat(A, 0); A[#A] = Vec( sum(m=0, #A, ((1+X)^m - 1)^m / (Ser(A) - 1 + (1+X)^m)^(m+1) ) )[#A]); A[n+1]}
for(n=0, 30, print1(a(n), ", "))
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Feb 07 2019
STATUS
approved