Triangular array read by rows. T(n,k) is the number of labeled digraphs on n nodes with exactly k isolated nodes. 0<=k<=n.

A217580

Triangular array read by rows. T(n,k) is the number of labeled digraphs on n nodes with exactly k isolated nodes. 0<=k<=n.

Terms

    a(0) =1a(1) =0a(2) =1a(3) =3a(4) =0a(5) =1a(6) =54a(7) =9a(8) =0a(9) =1a(10) =3861a(11) =216a(12) =18a(13) =0a(14) =1a(15) =1028700a(16) =19305a(17) =540a(18) =30a(19) =0a(20) =1a(21) =1067510583a(22) =6172200a(23) =57915a(24) =1080a(25) =45a(26) =0a(27) =1a(29) =7472574081a(30) =21602700

External references