A268309 - cp's OEIS frontend

A268309 Number of n X n symmetric matrices with nonnegative integer entries and without zero rows or columns such that the sum of all entries is equal to n^2.

n	a(n)
0	1
1	1
2	7
3	347
4	83785
5	85813461
6	362302219609
7	6227015262941276
8	433865390872310453097
9	122285854086662347886884837
10	139236232279790897112737794283927
11	639720298831885406784643598607618757713
12	11848024220605180271987429760766015754937928643

[1, 1, 7, 347, 83785, 85813461, 362302219609, 6227015262941276, 433865390872310453097, 122285854086662347886884837, 139236232279790897112737794283927, 639720298831885406784643598607618757713, 11848024220605180271987429760766015754937928643]

cp's OEIS Frontend

A268309 Number of n X n symmetric matrices with nonnegative integer entries and without zero rows or columns such that the sum of all entries is equal to n^2.

Table of values

List of values