Number of preferential arrangements (or simple hierarchies) of 2*n labeled elements with two kinds of elements (where each kind has n elements).
A099880
Number of preferential arrangements (or simple hierarchies) of 2*n labeled elements with two kinds of elements (where each kind has n elements).
Terms
- a(0) =1a(1) =2a(2) =18a(3) =260a(4) =5250a(5) =136332a(6) =4327092a(7) =162309576a(8) =7024896450a(9) =344582629820
External references
- oeis: A099880