Triangle: Number of asymmetric semigroups of order n with k idempotents.

Terms

a(0) =1a(1) =2a(2) =1a(3) =3a(4) =9a(5) =3a(6) =11a(7) =37a(8) =52a(9) =12a(10) =112a(11) =224a(12) =434a(13) =383a(14) =68a(15) =4398a(16) =1984a(17) =3976a(18) =5568a(19) =3256a(20) =502a(21) =1181185a(22) =47622a(23) =44581a(24) =74851a(25) =74604a(26) =31881a(27) =4158