Number of n X n matrices with nonnegative entries and every row and column sum 2.
A000681
Number of n X n matrices with nonnegative entries and every row and column sum 2.
Terms
- a(0) =1a(1) =1a(2) =3a(3) =21a(4) =282a(5) =6210a(6) =202410a(7) =9135630a(8) =545007960a(9) =41514583320
External references
- oeis: A000681