Number of semi-regular digraphs (with loops) on n unlabeled nodes with each node having out-degree 3.

A005535

Number of semi-regular digraphs (with loops) on n unlabeled nodes with each node having out-degree 3.

Terms

    a(0) =1a(1) =19a(2) =916a(3) =91212a(4) =12888450a(5) =2411213698a(6) =575737451509

External references