Number of semi-regular digraphs (with loops) on n unlabeled nodes with each node having out-degree 2.
A003286
Number of semi-regular digraphs (with loops) on n unlabeled nodes with each node having out-degree 2.
Terms
- a(0) =1a(1) =7a(2) =66a(3) =916a(4) =16816a(5) =373630a(6) =9727010a(7) =289374391a(8) =9677492899a(9) =359305262944
External references
- oeis: A003286