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A317285 Number of permutations of [n] with exactly five increasing runs of even length. 2
50521, 1629248, 32918922, 617859020, 11668739836, 217316513198, 4043244094251, 76688877688570, 1487035437929625, 29470163960950720, 598896893196470516, 12504145259394103084, 268208623687371202156, 5911352523792061709194, 133914475861667199021171 (list; graph; refs; listen; history; text; internal format)
OFFSET

10,1

LINKS

Alois P. Heinz, Table of n, a(n) for n = 10..470

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, 6)

    end:

a:= n-> coeff(b(n, 0$2), x, 5):

seq(a(n), n=10..30);

CROSSREFS

Column k=5 of A097592.

Sequence in context: A231918 A029823 A302902 * A253032 A251486 A268469

Adjacent sequences:  A317282 A317283 A317284 * A317286 A317287 A317288

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Jul 25 2018

STATUS

approved

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Last modified May 23 23:07 EDT 2022. Contains 353993 sequences. (Running on oeis4.)