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A293914 Number of linear chord diagrams having n chords and minimal chord length one.

%I A293914 #9 Oct 25 2017 18:08:00
%S A293914 1,2,10,69,616,6740,87291,1305710,22149226,420113979,8810083360,
%T A293914 202397302184,5054993327385,136370982998354,3951907646699026,
%U A293914 122432049983991285,4038019273764782056,141261207847788852620,5224370049771189478371,203670050053447478737214
%N A293914 Number of linear chord diagrams having n chords and minimal chord length one.
%H A293914 Alois P. Heinz, <a href="/A293914/b293914.txt">Table of n, a(n) for n = 1..404</a>
%F A293914 a(n) ~ (1 - exp(-1)) * 2^(n + 1/2) * n^n / exp(n). - _Vaclav Kotesovec_, Oct 25 2017
%p A293914 a:= proc(n) option remember; `if`(n<3, n, (4*n-6)*
%p A293914       a(n-1)-2*(2*n^2-8*n+7)*a(n-2)-(2*n-5)*a(n-3))
%p A293914     end:
%p A293914 seq(a(n), n=1..25);
%Y A293914 Column k=1 of A293881.
%K A293914 nonn
%O A293914 1,2
%A A293914 _Alois P. Heinz_, Oct 19 2017