Irregular triangle read by rows: T(n,k) is the number of k-partitions of {1..2n} that are invariant under a permutation consisting of n 2-cycles (1 <= k <= 2n).
A293181
Irregular triangle read by rows: T(n,k) is the number of k-partitions of {1..2n} that are invariant under a permutation consisting of n 2-cycles (1 <= k <= 2n).
Terms
- a(0) =1a(1) =1a(2) =1a(3) =3a(4) =2a(5) =1a(6) =1a(7) =7a(8) =10a(9) =9a(10) =3a(11) =1a(12) =1a(13) =15a(14) =38a(15) =53a(16) =34a(17) =18a(18) =4a(19) =1a(20) =1a(21) =31a(22) =130a(23) =265a(24) =261a(25) =195a(26) =80a(27) =30a(28) =5a(29) =1
External references
- oeis: A293181