A321112 Number of permutations p of [n] such that in 0p the largest up-jump equals five and no down-jump is larger than 2.

10, 58, 340, 2014, 11888, 69274, 401648, 2329526, 13514794, 78445016, 455726404, 2650463368, 15433424116, 89977250572, 525210971550, 3069436719818, 17959557595206, 105203403819650, 616942677047888, 3621795968081798, 21283870741193560, 125201162038738596

Offset

5,1

Links

Alois P. Heinz, Table of n, a(n) for n = 5..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))(5):
seq(a(n), n=5..30);

Crossrefs

Column k=5 of A291680.

Sequence in context: A055583 A242202 A125320 * A126730 A126478 A223470

Adjacent sequences: A321109 A321110 A321111 * A321113 A321114 A321115

Keyword

nonn

Author

Alois P. Heinz, Oct 27 2018

Status

approved