Array read by antidiagonals: T(n,k) is the number of functions f: X->Y, where X is a subset of Y, |X| = n, |Y| = n+k, such that for every x in X, f(f(x)) != x.
A334014
Array read by antidiagonals: T(n,k) is the number of functions f: X->Y, where X is a subset of Y, |X| = n, |Y| = n+k, such that for every x in X, f(f(x)) != x.
Terms
- a(0) =1a(1) =1a(2) =0a(3) =1a(4) =1a(5) =0a(6) =1a(7) =2a(8) =3a(9) =2a(10) =1a(11) =3a(12) =8a(13) =18a(14) =30a(15) =1a(16) =4a(17) =15a(18) =52a(19) =163a(20) =444a(21) =1a(22) =5a(23) =24a(24) =110a(25) =478a(26) =1950a(27) =7360a(28) =1a(29) =6
External references
- oeis: A334014