OFFSET
1,2
COMMENTS
Arises from counting coverings of a genus g=2 Riemann surface - expansion of generating function A_g(q) = sum_{n>=0} a_{n,g} q^n where a_{n,g} = sum_{mu a partition of n} (f^mu/n!)^{2-2g}; note that A_0(q) = e^q and A_1(q) = prod_{i>=1} 1/(1-q^i).
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..60
MATHEMATICA
(* version 4.0 *) Needs["DiscreteMath`Combinatorica`"]; Table[Tr[(n!/ (NumberOfTableaux /@ Partitions[n]))^2], {n, 20}] (* Wouter Meeussen, Sep 30 2010 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Bruce E. Sagan, Apr 06 2002
EXTENSIONS
Terms 8 to 20 added by Wouter Meeussen, Sep 30 2010
STATUS
approved