Triangle T(n,k) read by rows: number of labeled 2-regular digraphs (multiple arcs and loops allowed) on n nodes with k components.
A307804
Triangle T(n,k) read by rows: number of labeled 2-regular digraphs (multiple arcs and loops allowed) on n nodes with k components.
Terms
- a(0) =1a(1) =0a(2) =1a(3) =0a(4) =2a(5) =1a(6) =0a(7) =14a(8) =6a(9) =1a(10) =0a(11) =201a(12) =68a(13) =12a(14) =1a(15) =0a(16) =4704a(17) =1285a(18) =200a(19) =20a(20) =1a(21) =0a(22) =160890a(23) =36214a(24) =4815a(25) =460a(26) =30a(27) =1a(28) =0a(29) =7538040
External references
- oeis: A307804