OFFSET
0,2
FORMULA
Number triangle T(n,k)=[k<=n]*(3n)!/(3k)!
EXAMPLE
Triangle begins
1,
6, 1,
720, 120, 1,
362880, 60480, 504, 1,
479001600, 79833600, 665280, 1320, 1,
1307674368000, 217945728000, 1816214400, 3603600, 2730, 1
MATHEMATICA
Flatten[Table[(3n)!/(3k)!, {n, 0, 10}, {k, 0, n}]] (* Harvey P. Dale, Jan 19 2013 *)
CROSSREFS
KEYWORD
AUTHOR
Paul Barry, May 25 2006
STATUS
approved