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A264467 Number of permutations of [n] with exactly eight (possibly overlapping) occurrences of the generalized pattern 23-1. 2
55, 1393, 22180, 290341, 3443222, 39212955, 439762906, 4922646194, 55440198721, 631281758915, 7290146619344, 85550258610256, 1021466597564828, 12418915430929303, 153814790549535203, 1941191617618161308, 24964754218212162461, 327159226788279647296 (list; graph; refs; listen; history; text; internal format)
OFFSET
7,1
LINKS
EXAMPLE
a(7) = 55: 2567341, 3456712, 3456721, ..., 6745213, 6745312, 6745321.
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, 9), polynom), j=1..o))
end:
a:= n-> coeff(b(n, 0), x, 8):
seq(a(n), n=7..25);
CROSSREFS
Column k=8 of A260670.
Sequence in context: A297753 A134291 A157096 * A017771 A322502 A271796
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Nov 14 2015
STATUS
approved

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Last modified July 22 00:08 EDT 2024. Contains 374478 sequences. (Running on oeis4.)