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

A324375

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

Terms

    a(0) =1a(1) =1a(2) =2a(3) =3a(4) =5a(5) =13a(6) =29a(7) =68a(8) =165a(9) =339a(10) =1249a(11) =3706a(12) =11749a(13) =39151a(14) =105714a(15) =321361a(16) =938529a(17) =4112583a(18) =16778058a(19) =64073812a(20) =260625900a(21) =917269164a(22) =3451696842a(23) =13068376545a(24) =48655092849

External references