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A272168 a(n) = Product_{k=0..n} (k^2-k)!. 2
1, 1, 2, 1440, 689762304000, 1678124094566146045378560000000, 445127215203413988036981576746329306509322538188800000000000000 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
COMMENTS
The next term has 114 digits.
LINKS
FORMULA
a(n) ~ c * n^(n*(2*n^2 + 1)/3) * (2*Pi)^(n/2) / exp(5*n^3/9 + n/2 - Zeta(3) / (2*Pi^2)), where c = Product_{k>=2} (k*(k-1))!/stirling(k*(k-1)) = 1.086533635964823338078329042... and stirling(n) = sqrt(2*Pi*n) * n^n / exp(n) is the Stirling approximation of n!.
MATHEMATICA
Table[Product[(k^2-k)!, {k, 0, n}], {n, 0, 8}]
CROSSREFS
Sequence in context: A227247 A362207 A294321 * A173131 A160087 A170993
KEYWORD
nonn,easy
AUTHOR
Vaclav Kotesovec, Apr 21 2016
STATUS
approved

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Last modified April 14 10:04 EDT 2024. Contains 371657 sequences. (Running on oeis4.)