Irregular table read by rows: The number of acyclic digraphs on n labeled nodes with k descents.

Terms

a(0) =1a(1) =2a(2) =1a(3) =8a(4) =11a(5) =5a(6) =1a(7) =64a(8) =161a(9) =167a(10) =102a(11) =39a(12) =9a(13) =1a(14) =1024a(15) =3927a(16) =6698a(17) =7185a(18) =5477a(19) =3107a(20) =1329a(21) =423a(22) =96a(23) =14a(24) =1a(25) =32768a(26) =172665a(27) =419364a(28) =656733a(29) =757939