Number of n X n nonnegative integer symmetric matrices with all row and column sums equal to n.
A333739
Number of n X n nonnegative integer symmetric matrices with all row and column sums equal to n.
Terms
- a(0) =1a(1) =1a(2) =3a(3) =23a(4) =641a(5) =62781a(6) =22393101a(7) =29445929253
External references
- oeis: A333739