A263888 Number of permutations of [n] containing exactly four occurrences of the consecutive pattern 132.

105, 7968, 306729, 8862336, 221041785, 5090751360, 112456455285, 2438635714560, 52685573396310, 1145097655557120, 25201633254603750, 564111809386352640, 12881077471698335550, 300654388617807974400, 7182803417002318476630, 175794354355113443819520

Offset

9,1

Links

Alois P. Heinz, Table of n, a(n) for n = 9..100

Formula

a(n) = A197365(n,4).

Example

a(9) = 105: 132547698, 132548697, 132549687, ..., 192835476, 192836475, 192837465.

Maple

b:= proc(u, o, t) option remember; series(`if`(u+o=0, 1,
      add(b(u-j, o+j-1, 0)*`if`(j<=t, x, 1), j=1..u)+
      add(b(u+j-1, o-j, j-1), j=1..o)), x, 5)
    end:
a:= n-> coeff(b(n, 0$2), x, 4):
seq(a(n), n=9..35);

Crossrefs

Column k=4 of A197365.

Sequence in context: A075924 A359991 A199353 * A269474 A255497 A094075

Adjacent sequences: A263885 A263886 A263887 * A263889 A263890 A263891

Keyword

nonn

Author

Alois P. Heinz, Oct 28 2015

Status

approved