T(n,k) is the number of partial bijections (or subpermutations) of an n-element set with exactly k fixed points.
A144088
T(n,k) is the number of partial bijections (or subpermutations) of an n-element set with exactly k fixed points.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =4a(4) =2a(5) =1a(6) =18a(7) =12a(8) =3a(9) =1a(10) =108a(11) =72a(12) =24a(13) =4a(14) =1a(15) =780a(16) =540a(17) =180a(18) =40a(19) =5a(20) =1a(21) =6600a(22) =4680a(23) =1620a(24) =360a(25) =60a(26) =6a(27) =1a(28) =63840a(29) =46200
External references
- oeis: A144088