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A323717
a(n) = Product_{k=0..n} (n! + k!).
5
2, 4, 36, 4704, 23400000, 7778123781120, 245221791787632844800, 980866487456532919096049664000, 647456833933936977045736601678008811520000, 89423837415458106416291101560480526982914768896000000000
OFFSET
0,1
LINKS
FORMULA
a(n) ~ 2^((n+3)/2) * Pi^((n+1)/2) * n^((n+1)*(2*n+1)/2) / exp(n^2 + n - 1/12).
a(n) ~ 2 * (n!)^(n+1). - Vaclav Kotesovec, Mar 28 2019
MATHEMATICA
Table[Product[n!+k!, {k, 0, n}], {n, 0, 10}]
PROG
(Magma) F:= Factorial; [(&*[F(n) + F(j): j in [0..n]]): n in [0..20]]; // G. C. Greubel, Aug 30 2023
(SageMath) f=factorial; [product(f(n) + f(k) for k in range(n+1)) for n in range(21)] # G. C. Greubel, Aug 30 2023
CROSSREFS
KEYWORD
nonn
AUTHOR
Vaclav Kotesovec, Jan 25 2019
STATUS
approved