A264459 Number of permutations of [n] with exactly ten (possibly overlapping) occurrences of the generalized pattern 12-3.

1, 28, 594, 10735, 169753, 2438911, 32897588, 427124523, 5433554133, 68546679923, 864462182024, 10957001813778, 140087846414020, 1811142056680743, 23718822943004668, 315018653189118579, 4246519279200474842, 58132401024629625298, 808428792791995327013

Offset

6,2

Links

Alois P. Heinz, Table of n, a(n) for n = 6..500

Example

a(6) = 1: 123456.
a(7) = 28: 1236475, 1236547, 1236574, 1236745, 1236754, 1237456, 1243576, 1245376, 1245736, 1245763, 1246357, 1253467, 1324567, 1342567, 1345267, 1345627, 1345672, 2134567, 2314567, 2341567, 2345167, 2345617, 2345671, 3124567, 4123567, 5123467, 6123457, 7123456.

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, 11), polynom), j=1..o))
    end:
a:= n-> coeff(b(n, 0), x, 10):
seq(a(n), n=6..25);

Crossrefs

Column k=10 of A260665.

Sequence in context: A234618 A107397 A053110 * A004371 A283096 A089908

Adjacent sequences: A264456 A264457 A264458 * A264460 A264461 A264462

Keyword

nonn

Author

Alois P. Heinz, Nov 14 2015

Status

approved