A333739 Number of n X n nonnegative integer symmetric matrices with all row and column sums equal to n.

1, 1, 3, 23, 641, 62781, 22393101, 29445929253, 144413237202513, 2664174112921403401, 186127457781265060985293, 49509854244685925218197355989, 50364892612276937755557718571828543, 196663809308382999799947201118326883990475

Offset: 0

Author

Andrew Howroyd, Apr 08 2020

Keywords

• nonn

Crossrefs

Main diagonal of A188403.