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

Author

Alois P. Heinz, Oct 27 2018

Keywords

• nonn

Links

• Alois P. Heinz, Table of n, a(n) for n = 7..1000

Crossrefs

Column k=7 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))(7):
seq(a(n), n=7..30);