A321114 Number of permutations p of [n] such that in 0p the largest up-jump equals seven and no down-jump is larger than 2.

74, 528, 3550, 23284, 151096, 974472, 6252218, 39892080, 253727936, 1611713082, 10230277342, 64911693746, 411813289010, 2612751224650, 16579665387410, 105238154698686, 668214471729004, 4244427360639456, 26970709343926262, 171451330997483406, 1090351846894142818

Offset

7,1

Links

Alois P. Heinz, Table of n, a(n) for n = 7..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))(7):
seq(a(n), n=7..30);

Crossrefs

Column k=7 of A291680.

Sequence in context: A238022 A296025 A204362 * A205584 A280402 A250913

Adjacent sequences: A321111 A321112 A321113 * A321115 A321116 A321117

Keyword

nonn

Author

Alois P. Heinz, Oct 27 2018

Status

approved