OFFSET
0,3
COMMENTS
Compare g.f. to: Sum_{n>=0} Product_{k=1..n} ((1+x)^k - 1), which is the g.f. of A179525.
LINKS
Vaclav Kotesovec, Table of n, a(n) for n = 0..170
Hsien-Kuei Hwang, Emma Yu Jin, Asymptotics and statistics on Fishburn matrices and their generalizations, arXiv:1911.06690 [math.CO], 2019.
FORMULA
a(n) ~ 2 * 12^(n+1) * n^(n+1/2) / (exp(n+Pi^2/24) * Pi^(2*n+3/2)). - Vaclav Kotesovec, May 07 2014
EXAMPLE
G.f.: A(x) = 1 + x + 3*x^2 + 11*x^3 + 55*x^4 + 339*x^5 + 2499*x^6 +...
such that, by definition,
A(x) = 1 + (1+x)*((1+x)-1) + (1+x)^2*((1+x)-1)*((1+x)^2-1) + (1+x)^3*((1+x)-1)*((1+x)^2-1)*((1+x)^3-1) + (1+x)^4*((1+x)-1)*((1+x)^2-1)*((1+x)^3-1)*((1+x)^4-1) +...
PROG
(PARI) {a(n)=polcoeff(sum(m=0, n, (1+x)^m*prod(k=1, m, (1+x)^k-1) +x*O(x^n)), n)}
for(n=0, 25, print1(a(n), ", "))
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Feb 18 2012
STATUS
approved