Number of ways of transforming a set of n indistinguishable objects into n singletons via a sequence of n-1 refinements.

A002846

Number of ways of transforming a set of n indistinguishable objects into n singletons via a sequence of n-1 refinements.

Terms

    a(0) =1a(1) =1a(2) =1a(3) =2a(4) =4a(5) =11a(6) =33a(7) =116a(8) =435a(9) =1832a(10) =8167a(11) =39700a(12) =201785a(13) =1099449a(14) =6237505a(15) =37406458a(16) =232176847a(17) =1513796040a(18) =10162373172a(19) =71158660160a(20) =511957012509

External references