A317287 Number of permutations of [n] with exactly seven increasing runs of even length.

199360981, 11190963430, 378291607803, 11014069796526, 305943708449074, 8211684416287224, 215906484804391566, 5654455021954104792, 148657867362265421769, 3937297418900898841450, 105451222548147683308147, 2864250745636538809593802, 79027581972356621300952774

Offset

14,1

Links

Alois P. Heinz, Table of n, a(n) for n = 14..469

Maple

b:= proc(u, o, t) option remember; series(`if`(u+o=0, x^t,
      add(b(u+j-1, o-j, irem(t+1, 2)), j=1..o)+
      add(b(u-j, o+j-1, 0)*x^t, j=1..u)), x, 8)
    end:
a:= n-> coeff(b(n, 0$2), x, 7):
seq(a(n), n=14..30);

Crossrefs

Column k=7 of A097592.

Sequence in context: A251514 A268844 A015368 * A132205 A358019 A015427

Adjacent sequences: A317284 A317285 A317286 * A317288 A317289 A317290

Keyword

nonn

Author

Alois P. Heinz, Jul 25 2018

Status

approved