This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A115294 #7 Jun 11 2017 14:22:07
%S A115294 1,4,11,25,47,79,122,175,239,314,399,495,602,719,847,986,1135,1295,
%T A115294 1466,1647,1839,2042,2255,2479,2714,2959,3215,3482,3759,4047,4346,
%U A115294 4655,4975,5306,5647,5999,6362,6735,7119,7514,7919,8335,8762,9199,9647,10106
%N A115294 Diagonal sums of correlation triangle for (1+x)^3/(1-x).
%C A115294 Diagonal sums of number triangle A115292.
%H A115294 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1,1,-2,1).
%F A115294 G.f.: (1+x)^2*(1+x^2)^3/((1-x)^2*(1-x^3)); a(n)=sum{k=0..floor(n/2), sum{j=0..n-k, [j<=k]*A115291(k-j)*[j<=n-2k]*A115291(n-2k-j)}}.
%t A115294 LinearRecurrence[{2,-1,1,-2,1},{1,4,11,25,47,79,122,175,239},50] (* _Harvey P. Dale_, Jun 11 2017 *)
%K A115294 easy,nonn
%O A115294 0,2
%A A115294 _Paul Barry_, Jan 19 2006