OFFSET
0,3
LINKS
Robert Israel, Table of n, a(n) for n = 0..508
FORMULA
log(a(n)) ~ n*(log(n) - log(log(n)) + (log(log(n)) - 1)/log(n)). - Vaclav Kotesovec, Jan 10 2023
G.f. A(x) = 1 + x*Sum_{n>=0} x^n/n! * ( d^n/dy^n (1+y)^n/(1 - x*(1+y)^n) ) evaluated at y = 0. - Paul D. Hanna, Nov 13 2024
EXAMPLE
G.f.: A(x) = 1 + x + 2*x^2 + 4*x^3 + 11*x^4 + 41*x^5 + 189*x^6 + 1020*x^7 + 6277*x^8 + 43262*x^9 + 328963*x^10 + ...
MAPLE
seq(add(binomial((n-k)*k, k), k=0..n), n=0..30); # Robert Israel, Nov 27 2017
MATHEMATICA
Table[Sum[Binomial[(n-k)*k, k], {k, 0, n}], {n, 0, 30}]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vaclav Kotesovec, Nov 27 2017
STATUS
approved