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

6,1

Links

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

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);

Crossrefs

Column k=6 of A291680.

Sequence in context: A156339 A268331 A125336 * A126494 A374489 A027001

Adjacent sequences: A321110 A321111 A321112 * A321114 A321115 A321116

Keyword

nonn

Author

Alois P. Heinz, Oct 27 2018

Status

approved