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A264455 Number of permutations of [n] with exactly six (possibly overlapping) occurrences of the generalized pattern 12-3. 2
1, 17, 238, 2956, 33343, 355182, 3681762, 37839385, 389940538, 4056942189, 42796503464, 458995025669, 5013561835833, 55832699192796, 634322118799677, 7354538207075076, 87032355679553323, 1051183375285792257, 12956782873283747998, 162950022525866642259 (list; graph; refs; listen; history; text; internal format)
OFFSET

5,2

LINKS

Alois P. Heinz, Table of n, a(n) for n = 5..500

EXAMPLE

a(5) = 1: 12345.

a(6) = 17: 124365, 124635, 124653, 125346, 132456, 134256, 134526, 134562, 213456, 231456, 234156, 234516, 234561, 312456, 412356, 512346, 612345.

MAPLE

b:= proc(u, o) option remember; `if`(u+o=0, 1, add(

       b(u-j, o+j-1), j=1..u)+add(convert(series(

       b(u+j-1, o-j)*x^(o-j), x, 7), polynom), j=1..o))

    end:

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

seq(a(n), n=5..25);

CROSSREFS

Column k=6 of A260665.

Sequence in context: A016166 A206354 A125474 * A142126 A251769 A290340

Adjacent sequences:  A264452 A264453 A264454 * A264456 A264457 A264458

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Nov 14 2015

STATUS

approved

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Last modified April 9 06:32 EDT 2020. Contains 333343 sequences. (Running on oeis4.)