|
%I #5 Nov 21 2013 12:49:04
%S 1,1,6,18,70,246,924,3412,12870,48550,184756,705180,2704156,10399676,
%T 40116600,155114088,601080390,2333593350,9075135300,35345215180,
%U 137846528820,538257689684,2104098963720,8233430022168,32247603683100
%N Expansion of 1/sqrt(1-4x)-x/sqrt(1-4x^2).
%C Partial sums are A129368.
%F a(n)=C(2n,n)-C(n-1,(n-1)/2)(1-(-1)^n)/2;
%t CoefficientList[Series[1/Sqrt[1-4x]-x/Sqrt[1-4x^2],{x,0,30}],x] (* _Harvey P. Dale_, Feb 02 2012 *)
%K easy,nonn
%O 0,3
%A _Paul Barry_, Apr 11 2007
|
