OFFSET
1,1
LINKS
Ivan Neretin, Table of n, a(n) for n = 1..4950
Eric Weisstein's World of Mathematics, Factorial.
Eric Weisstein's World of Mathematics, Multifactorial.
EXAMPLE
Triangle begins
Row 1: 2! = 2
Row 2: 3!! = 3*1 = 3, 3! = 3*2*1 = 6
Row 3: 4!!! = 4*1 = 4, 4!! = 4*2 = 8, 4! = 4*3*2*1 = 24,
Row 4: 5!!!! = 5*1 = 5, 5!!! = 5*2 = 10, 5!! = 5*3 = 15, 5! = 5*4*3*2*1 = 120,
...
MATHEMATICA
Flatten[Table[Times @@ Range[n, 1, -i], {n, 12}, {i, n - 1, 1, -1}]] (* Ivan Neretin, May 09 2015 *)
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Rick L. Shepherd, Jul 16 2003
STATUS
approved