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A264469 Number of permutations of [n] with exactly ten (possibly overlapping) occurrences of the generalized pattern 23-1.

%I A264469 #5 Nov 14 2015 17:01:15
%S A264469 4,432,10723,185030,2679741,35436222,447105877,5525656829,67836294722,
%T A264469 834260210092,10332749157300,129333951912536,1639800629344515,
%U A264469 21092071947142268,275512690552878512,3657197040905519063,49353853545913899116,677272710732166102115
%N A264469 Number of permutations of [n] with exactly ten (possibly overlapping) occurrences of the generalized pattern 23-1.
%H A264469 Alois P. Heinz, <a href="/A264469/b264469.txt">Table of n, a(n) for n = 7..500</a>
%e A264469 a(7) = 4: 4567231, 5672341, 5673412, 5673421.
%p A264469 b:= proc(u, o) option remember; `if`(u+o=0, 1, add(
%p A264469       b(u-j, o+j-1), j=1..u) +add(convert(series(
%p A264469       b(u+j-1, o-j)*x^u, x, 11), polynom), j=1..o))
%p A264469     end:
%p A264469 a:= n-> coeff(b(n, 0), x, 10):
%p A264469 seq(a(n), n=7..25);
%Y A264469 Column k=10 of A260670.
%K A264469 nonn
%O A264469 7,1
%A A264469 _Alois P. Heinz_, Nov 14 2015