Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #2 Mar 30 2012 18:59:25
%S 1,0,-1,-1,1,2,1,-3,-5,-1,11,15,-5,-44,-41,51,169,85,-303,-611,-15,
%T 1513,2021,-1271,-6827,-5673,10361,28301,10141,-61102,-107015,20109,
%U 310387,356515,-354349,-1421913,-936805,2567875,5930631,972819,-14696329
%N A transform of the Catalan numbers with a simple Hankel transform.
%C Hankel transform is A157128. Partial sums of A157125.
%F G.f.: (sqrt(1+x^2+4x^3)-sqrt(1+x^2))/(2*sqrt(1+x^2));
%F a(n)=sum{k=0..n, A157125(k)};
%K easy,sign
%O 0,6
%A _Paul Barry_, Feb 23 2009