Number of endofunctions on [n] such that no element has a preimage of cardinality two.

A245406

Number of endofunctions on [n] such that no element has a preimage of cardinality two.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =9a(4) =76a(5) =825a(6) =10206a(7) =143521a(8) =2313200a(9) =42482313a(10) =875799550a(11) =19972186311a(12) =498430219464

External references