OFFSET
1,2
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..700
Wolfgang Unger, Combinatorics of Lattice QCD at Strong Coupling, arXiv:1411.4493 [hep-lat], 2014.
FORMULA
a(n) = 6*(3*n-2)! / (n!*(n-1)!*(n+2)!). - Alois P. Heinz, Apr 11 2012
n*(n+2)*a(n) - 3*(3*n-2)*(3*n-4)*a(n-1) = 0. - R. J. Mathar, Aug 10 2015
G.f.: x*3F2(1,2/3,4/3;2,4;27x). - R. J. Mathar, Aug 10 2015
MAPLE
a:= n-> 6 *(3*n-2)! / (n! *(n-1)! *(n+2)!):
seq(a(n), n=1..25); # Alois P. Heinz, Apr 11 2012
MATHEMATICA
(* first do *) Needs["DiscreteMath`Combinatorica`"] (* then *) Table[ NumberOfTableaux@{n, n - 1, n - 1}, {n, 18}]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Robert G. Wilson v, Nov 15 2006
STATUS
approved