login
A255359
a(n) = Product_{k=0..n} (k^4)!.
7
1, 1, 20922789888000
OFFSET
0,3
COMMENTS
The next term a(3) has 135 digits.
LINKS
FORMULA
a(n) ~ c * n^(1 + 28*n/15 + 4*n^3/3 + 2*n^4 + 4*n^5/5) * (2*Pi)^(n/2) / exp(19*n/9 + n^4/2 + 9*n^5/25), where c = A255438 = 6.644987918706354049483118... .
a(n) = Product_{j=1..n^4} j^(n - ceiling(j^(1/4)) + 1). - Vaclav Kotesovec, Apr 25 2024
MATHEMATICA
Table[Product[(k^4)!, {k, 0, n}], {n, 0, 5}]
Table[Product[j^(n - Ceiling[j^(1/4)] + 1), {j, 1, n^4}], {n, 0, 5}] (* Vaclav Kotesovec, Apr 25 2024 *)
KEYWORD
nonn
AUTHOR
Vaclav Kotesovec, Feb 21 2015
STATUS
approved