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A319924 a(n) = A143565(2n,n) for n > 0, a(0) = 1.

%I A319924 #8 Oct 03 2018 18:23:19
%S A319924 1,3,13,61,281,1261,5545,24025,102961,437581,1847561,7759753,32449873,
%T A319924 135207801,561632401,2326762801,9617286241,39671305741,163352435401,
%U A319924 671560012201,2756930576401,11303415363241,46290177201841,189368906734801,773942488394401
%N A319924 a(n) = A143565(2n,n) for n > 0, a(0) = 1.
%H A319924 Alois P. Heinz, <a href="/A319924/b319924.txt">Table of n, a(n) for n = 0..1658</a>
%F A319924 a(n) = A143565(2n,n) for n > 0, a(0) = 1.
%F A319924 a(n) = 1 + 2 * A002457(n-1) = 1 + 2 * (2*n-1)!/(n-1)!^2 for n > 0, a(0) = 1.
%p A319924 a:= proc(n) option remember; `if`(n<2, 2*n+1,
%p A319924       ((15*n^2-29*n+10)*a(n-1)-(6*n-2)*(2*n-3)*
%p A319924        a(n-2))/((n-1)*(3*n-4)))
%p A319924     end:
%p A319924 seq(a(n), n=0..30);
%Y A319924 Cf. A002457, A143565.
%K A319924 nonn
%O A319924 0,2
%A A319924 _Alois P. Heinz_, Oct 01 2018