OFFSET
0,2
FORMULA
a(n) ~ c * n^(2*n^2 - 1/2) * 4^(n*(n+1)) * 3^(-n/2) * exp(5*Pi*n*(n+1)/(6*sqrt(3)) - 3*n^2), where c = 0.4612030005343304845802441101292774353695846313857765074861837886133930626...
MATHEMATICA
Table[Product[i^2+3*j^2, {i, 1, n}, {j, 1, n}], {n, 0, 8}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Vaclav Kotesovec, Dec 05 2023
STATUS
approved