Triangle read by rows: T(n,k) (0 <= k <= n) is the rank of the ideal I_r in the inverse semigroup D_n of all difunctional relations on an n-element set.
A294432
Triangle read by rows: T(n,k) (0 <= k <= n) is the rank of the ideal I_r in the inverse semigroup D_n of all difunctional relations on an n-element set.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =1a(4) =3a(5) =3a(6) =1a(7) =7a(8) =8a(9) =8a(10) =1a(11) =15a(12) =27a(13) =21a(14) =19a(15) =1a(16) =31a(17) =92a(18) =84a(19) =60a(20) =57a(21) =1a(22) =63a(23) =303a(24) =385a(25) =266a(26) =213a(27) =209a(28) =1a(29) =127
External references
- oeis: A294432