Triangle of numbers a(n,k), 0 <= k <= n: number of set partitions of {1,2,...,n} in which exactly k of the blocks have been distinguished.
A049020
Triangle of numbers a(n,k), 0 <= k <= n: number of set partitions of {1,2,...,n} in which exactly k of the blocks have been distinguished.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =2a(4) =3a(5) =1a(6) =5a(7) =10a(8) =6a(9) =1a(10) =15a(11) =37a(12) =31a(13) =10a(14) =1a(15) =52a(16) =151a(17) =160a(18) =75a(19) =15a(20) =1a(21) =203a(22) =674a(23) =856a(24) =520a(25) =155a(26) =21a(27) =1a(28) =877a(29) =3263
External references
- oeis: A049020