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A231166 Number of permutations of [n] avoiding simultaneously consecutive patterns 1243, 1342, and 1324. 4
1, 1, 2, 6, 21, 91, 467, 2755, 18523, 139740, 1169616, 10763807, 108028386, 1174391384, 13748315494, 172439034531, 2306986699190, 32792999417180, 493559520202535, 7841127918788283, 131127477517244419, 2302491655047553206, 42355105188617740229 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..70

A. Baxter, B. Nakamura, and D. Zeilberger, Automatic generation of theorems and proofs on enumerating consecutive Wilf-classes

S. Kitaev and T. Mansour, On multi-avoidance of generalized patterns

EXAMPLE

a(4) = 24 - 3: 1243, 1342, 1324 are avoided.

MAPLE

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

       add(b(u-j, o+j-1, `if`(t>0, t, 0), `if`(t>0, -j, 0)),

           j=`if`(s>0 and t>0, s+t-1, 1)..u)+

       add(b(u+j-1, o-j, `if`(t>0, t, 0), +j),

           j=1..`if`(s>0 and t<0 and -t<s, -t-1, o)))

    end:

a:= n-> b(n, 0$3):

seq(a(n), n=0..25);

CROSSREFS

Cf. A113228, A117156, A117226.

Sequence in context: A033540 A177479 A147719 * A115089 A304196 A266328

Adjacent sequences:  A231163 A231164 A231165 * A231167 A231168 A231169

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Nov 04 2013

STATUS

approved

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Last modified April 19 10:56 EDT 2019. Contains 322258 sequences. (Running on oeis4.)