A321113 Number of permutations p of [n] such that in 0p the largest up-jump equals six and no down-jump is larger than 2.

26, 170, 1078, 6772, 42366, 263548, 1626122, 9993996, 61372356, 376754190, 2312742484, 14199997152, 87223775288, 536072840284, 3296748123732, 20287763348424, 124932460269594, 769857062164974, 4747179317544360, 29291823451184116, 180856995405347960

Offset: 6

Author

Alois P. Heinz, Oct 27 2018

Keywords

• nonn

Links

• Alois P. Heinz, Table of n, a(n) for n = 6..1000

Crossrefs

Column k=6 of A291680.

Programs

Maple

b:= proc(u, o, k) option remember; `if`(u+o=0, 1,
      add(b(u-j, o+j-1, k), j=1..min(2, u))+
      add(b(u+j-1, o-j, k), j=1..min(k, o)))
    end:
a:= n-> (k-> b(0, n, k)-b(0, n, k-1))(6):
seq(a(n), n=6..30);