Number of set partitions of [n] such that j is member of block b only if b = 1 or at least one of j-1, ..., j-6 is member of a block >= b-1.
A287669
Number of set partitions of [n] such that j is member of block b only if b = 1 or at least one of j-1, ..., j-6 is member of a block >= b-1.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =5a(4) =15a(5) =52a(6) =203a(7) =877a(8) =4140a(9) =21146a(10) =115903a(11) =677026a(12) =4190648a(13) =27356008a(14) =187573260a(15) =1346289439a(16) =10084570537a(17) =78630320221a(18) =636692795555
External references
- oeis: A287669