The number of endofunctions on n points such that all recurrent elements have at most 3 preimages and all nonrecurrent elements have at most 2 preimages.
A201996
The number of endofunctions on n points such that all recurrent elements have at most 3 preimages and all nonrecurrent elements have at most 2 preimages.
Terms
- a(0) =1a(1) =1a(2) =4a(3) =27a(4) =252a(5) =3000a(6) =43380a(7) =737730a(8) =14419440a(9) =318381840a(10) =7835486400a(11) =212634298800
External references
- oeis: A201996