OFFSET
0,9
COMMENTS
T(n,k) is the number of non-isomorphic n X n nonnegative integer symmetric matrices with all row and column sums equal to k and isomorphism being up to simultaneous permutation of rows and columns. The case that allows independent permutations of rows and columns is covered by A333737.
LINKS
Andrew Howroyd, Table of n, a(n) for n = 0..377 (antidiagonals 0..26)
EXAMPLE
Array begins:
==============================================
n\k | 0 1 2 3 4 5 6 7
----+-----------------------------------------
0 | 1 1 1 1 1 1 1 1 ...
1 | 1 1 1 1 1 1 1 1 ...
2 | 1 2 3 4 5 6 7 8 ...
3 | 1 2 5 8 14 20 30 40 ...
4 | 1 3 10 26 61 128 254 467 ...
5 | 1 3 16 60 243 800 2518 6999 ...
6 | 1 4 29 184 1228 7252 38194 175369 ...
7 | 1 4 45 488 6684 78063 772243 6254652 ...
...
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Andrew Howroyd, Apr 08 2020
STATUS
approved