OFFSET
2,2
LINKS
Joerg Arndt and Alois P. Heinz, Table of n, a(n) for n = 2..140
FORMULA
a(n) ~ 2*sqrt(3)/(exp(Pi^2/12)*sqrt(Pi)) * (6/Pi^2)^n * n! * sqrt(n). - Vaclav Kotesovec, Aug 27 2014
MATHEMATICA
b[n_, i_, t_] := b[n, i, t] = If[n == 0, 1, Expand[Sum[If[j == i, x, 1]*b[n-1, j, t + If[j>i, 1, 0]], {j, 0, t+1}]]]; a[n_] := Coefficient[b[n, -1, -1], x, 1]; Table[ a[n], {n, 2, 30}] (* Jean-François Alcover, Feb 10 2015, after A242153 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Joerg Arndt and Alois P. Heinz, May 05 2014
STATUS
approved