Triangular array read by rows. T(n,k) is the number of unlabeled directed graphs of n nodes that have exactly k isolated nodes.
A217654
Triangular array read by rows. T(n,k) is the number of unlabeled directed graphs of n nodes that have exactly k isolated nodes.
Terms
- a(0) =1a(1) =0a(2) =1a(3) =2a(4) =0a(5) =1a(6) =13a(7) =2a(8) =0a(9) =1a(10) =202a(11) =13a(12) =2a(13) =0a(14) =1a(15) =9390a(16) =202a(17) =13a(18) =2a(19) =0a(20) =1a(21) =1531336a(22) =9390a(23) =202a(24) =13a(25) =2a(26) =0a(27) =1a(28) =880492496a(29) =1531336
External references
- oeis: A217654