

A324403


a(n) = Product_{i=1..n, j=1..n} (i^2 + j^2).


16




OFFSET

1,1


COMMENTS

Next term is too long to be included.


LINKS

Table of n, a(n) for n=1..6.


FORMULA

a(n) ~ 2^(n*(n+1)  3/4) * exp(Pi*n*(n+1)/2  3*n^2 + Pi/12) * n^(2*n^2  1/2) / (Pi^(1/4) * Gamma(3/4)).
a(n) = 2*n^2*a(n1)*Product_{i=1..n1} (n^2 + i^2)^2.  Chai Wah Wu, Feb 26 2019


MATHEMATICA

Table[Product[i^2+j^2, {i, 1, n}, {j, 1, n}], {n, 1, 10}]


PROG

(PARI) a(n) = prod(i=1, n, prod(j=1, n, i^2+j^2)); \\ Michel Marcus, Feb 27 2019


CROSSREFS

Cf. A079478, A293290, A324402, A324443, A324426, A324437, A324438, A324439, A324440.
Sequence in context: A249177 A249178 A281650 * A214597 A283661 A067827
Adjacent sequences: A324400 A324401 A324402 * A324404 A324405 A324406


KEYWORD

nonn


AUTHOR

Vaclav Kotesovec, Feb 26 2019


STATUS

approved



