A325053 a(n) = Product_{i=0..n, j=0..n} (i! + j! + 1).

3, 81, 103680, 447180963840, 7014935716261432173527040, 1921470539412808834455592518302690305036517376000, 81601182941928855942156180258180656419177691149082352022004942698629910149621350400000

Offset

0,1

Links

Table of n, a(n) for n=0..6.

Formula

a(n) = A306729(n) * Product_{i=0..n, j=0..n} (1 + 1/(i! + j!)).

a(n) ~ c * A324569 * 2^(n^2/2 + 2*n) * Pi^(n^2/2 + n) * n^(2*n^3/3 + 2*n^2 + 11*n/6 + 5/2) / exp(8*n^3/9 + 2*n^2 + n), where c = Product_{i>=0, j>=0} (1 + 1/(i! + j!)) = 71.32069635593350979104242285703294604508330622582076432053456223608...

Mathematica

Table[Product[i! + j! + 1, {i, 0, n}, {j, 0, n}], {n, 0, 7}]

Crossrefs

Cf. A107254, A306729, A325052.

Sequence in context: A228971 A060722 A183502 * A134799 A055590 A037111

Adjacent sequences: A325050 A325051 A325052 * A325054 A325055 A325056

Keyword

nonn

Author

Vaclav Kotesovec, Mar 26 2019

Status

approved