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A264469
Number of permutations of [n] with exactly ten (possibly overlapping) occurrences of the generalized pattern 23-1.
2
4, 432, 10723, 185030, 2679741, 35436222, 447105877, 5525656829, 67836294722, 834260210092, 10332749157300, 129333951912536, 1639800629344515, 21092071947142268, 275512690552878512, 3657197040905519063, 49353853545913899116, 677272710732166102115
OFFSET
7,1
LINKS
EXAMPLE
a(7) = 4: 4567231, 5672341, 5673412, 5673421.
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^u, x, 11), polynom), j=1..o))
end:
a:= n-> coeff(b(n, 0), x, 10):
seq(a(n), n=7..25);
CROSSREFS
Column k=10 of A260670.
Sequence in context: A201980 A080321 A360844 * A369395 A172858 A125760
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Nov 14 2015
STATUS
approved