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

0,3

Links

Table of n, a(n) for n=0..13.

Crossrefs

Main diagonal of A188403.

Sequence in context: A127900 A229266 A143985 * A119669 A013391 A013389

Adjacent sequences: A333736 A333737 A333738 * A333740 A333741 A333742

Keyword

nonn

Author

Andrew Howroyd, Apr 08 2020

Status

approved