OFFSET
0,3
FORMULA
(Product of first n natural numbers )^(sum of first n natural numbers )
a(n) ~ (2*Pi)^(n*(n+1)/4) * n^(n*(n+1)*(2*n+1)/4) / exp((n+1)*(12*n^2 - 1)/24). - Vaclav Kotesovec, Apr 14 2023
EXAMPLE
a(5) = (5!)^(1+...+5) = 120^15 = 15407021574586368000000000000000. a(6) = 720^21.
MAPLE
seq(mul(mul(j^k, j=1..n), k=1..n), n=0..7); # Zerinvary Lajos, Jun 02 2007
MATHEMATICA
Table[n!^(n(n + 1)/2), {n, 1, 7}]
PROG
(PARI): for(n=1, 7, print1(n!^sum(k=1, n, k), ", "))
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Amarnath Murthy, Jan 02 2002
EXTENSIONS
More terms from Jason Earls and Robert G. Wilson v, Jan 04 2002
a(0)=1 prepended by Alois P. Heinz, Nov 13 2018
STATUS
approved