OFFSET
1,2
FORMULA
a(n) ~ A^2 * sqrt(2*Pi) * n^(n^2 + n - 1/3) / exp(n*(n+2)/2), where A = A074962 is the Glaisher-Kinkelin constant.
a(n) = n^n * Gamma(n)^(2*n-1) / BarnesG(n)^2. - Vaclav Kotesovec, Apr 21 2024
MATHEMATICA
Table[Product[(k^2-k)^k, {k, 2, n}], {n, 1, 10}]
Table[n^n * Gamma[n]^(2*n-1) / BarnesG[n]^2, {n, 1, 10}] (* Vaclav Kotesovec, Apr 21 2024 *)
PROG
(PARI) a(n) = prod(k=2, n, (k^2-k)^k); \\ Michel Marcus, Nov 18 2021
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vaclav Kotesovec, Apr 21 2016
EXTENSIONS
Definition corrected by Georg Fischer, Nov 18 2021
STATUS
approved