Triangle read by rows: T(n,k) is the number of k-regular digraphs on n unlabeled nodes, k = 0..n-1.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =1a(6) =1a(7) =2a(8) =2a(9) =1a(10) =1a(11) =2a(12) =5a(13) =2a(14) =1a(15) =1a(16) =4a(17) =23a(18) =23a(19) =4a(20) =1a(21) =1a(22) =4a(23) =92a(24) =415a(25) =92a(26) =4a(27) =1a(28) =1a(29) =7