%I A028339
%S A028339 1,9,86,950,12139,177331,2924172,53809164,1094071221,24372200061,
%T A028339 590546123298,15467069396610,435512515705695,13121113142970855,
%U A028339 421214220916438680,14354510691610713240,517596339235489288425
%N A028339 Coefficient of x^2 in expansion of (x+1)(x+3)...(x+2n-1).
%F A028339 sum[(-1)^(k+1-i) 2^(n-1) binomial(i-1, k) s1(n, i), i=k+1..n] with k 
               = 2, where s1(n, i) are unsigned Stirling numbers of the first kind 
               - Victor Adamchik (adamchik(AT)ux10.sp.cs.cmu.edu), Jan 23, 2001
%F A028339 E.g.f.: 1/8*(1-2*x)^(-1/2)*ln(1-2*x)^2. - Vladeta Jovovic (vladeta(AT)eunet.rs), 
               Feb 19 2003
%Y A028339 Cf. A028338.
%Y A028339 Contribution from Johannes W. Meijer (meijgia(AT)hotmail.com), Jun 08 
               2009: (Start)
%Y A028339 Equals third left hand column of A161198 triangle divided by 4.
%Y A028339 (End)
%Y A028339 Sequence in context: A029711 A015581 A152261 this_sequence A100814 A055725 
               A144852
%Y A028339 Adjacent sequences: A028336 A028337 A028338 this_sequence A028340 A028341 
               A028342
%K A028339 nonn
%O A028339 2,2
%A A028339 R. W. Gosper