Number of set partitions of [2n] in which the size of the first block is n.

A297926

Number of set partitions of [2n] in which the size of the first block is n.

Terms

    a(0) =1a(1) =1a(2) =6a(3) =50a(4) =525a(5) =6552a(6) =93786a(7) =1504932a(8) =26640900a(9) =514083570a(10) =10713538550a(11) =239342496120

External references