Number of singletons (strong fixed points) in pair-partitions.

A233481

Number of singletons (strong fixed points) in pair-partitions.

Terms

    a(0) =0a(1) =1a(2) =4a(3) =21a(4) =144a(5) =1245a(6) =13140a(7) =164745a(8) =2399040a(9) =39834585a(10) =742940100a(11) =15374360925a(12) =349484058000

External references