Triangle read by rows: number of commutative monoids of order n with k idempotents.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =3a(5) =1a(6) =2a(7) =9a(8) =6a(9) =2a(10) =1a(11) =26a(12) =30a(13) =16a(14) =5a(15) =1a(16) =98a(17) =142a(18) =111a(19) =54a(20) =15a(21) =1a(22) =455a(23) =718a(24) =713a(25) =482a(26) =215a(27) =53a(28) =3a(29) =4018