Number of permutations p of [n] whose absolute displacements |p(i)-i| are factorial numbers.

A324376

Number of permutations p of [n] whose absolute displacements |p(i)-i| are factorial numbers.

Terms

    a(0) =1a(1) =0a(2) =1a(3) =2a(4) =4a(5) =6a(6) =13a(7) =48a(8) =149a(9) =286a(10) =832a(11) =2304a(12) =6560a(13) =13630a(14) =35937a(15) =95816a(16) =242496a(17) =586480a(18) =1492057a(19) =3928292a(20) =10019073a(21) =24819960a(22) =63656169a(23) =163618614a(24) =416809221a(25) =1731461192a(26) =6214212533

External references