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A317286 Number of permutations of [n] with exactly six increasing runs of even length. 2
2702765, 117248463, 3118257980, 73830310655, 1708350797975, 38581706239634, 861226758827324, 19346584353278646, 439935779491790415, 10146028258663315691, 238129724283103648476, 5701793180421505562215, 139409020095464012520967, 3483089247393778028230622 (list; graph; refs; listen; history; text; internal format)
OFFSET

12,1

LINKS

Alois P. Heinz, Table of n, a(n) for n = 12..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, 7)

    end:

a:= n-> coeff(b(n, 0$2), x, 6):

seq(a(n), n=12..30);

CROSSREFS

Column k=6 of A097592.

Sequence in context: A251457 A178291 A212231 * A081409 A251997 A104848

Adjacent sequences:  A317283 A317284 A317285 * A317287 A317288 A317289

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Jul 25 2018

STATUS

approved

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Last modified May 22 09:50 EDT 2022. Contains 353949 sequences. (Running on oeis4.)