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 A110326 #5 Jun 13 2015 00:51:52 %S A110326 1,-1,-3,-2,-11,-3,-23,-4,-39,-5,-59,-6,-83,-7,-111,-8,-143,-9,-179, %T A110326 -10,-219,-11,-263,-12,-311,-13,-363,-14,-419,-15,-479,-16,-543,-17, %U A110326 -611,-18,-683,-19,-759,-20,-839,-21,-923,-22,-1011,-23,-1103,-24,-1199,-25,-1299,-26,-1403,-27,-1511,-28,-1623,-29,-1739 %N A110326 Diagonal sums of triangle A110324. %H A110326 <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (0,3,0,-3,0,1). %F A110326 G.f.: (1-x-6x^2+x^3+x^4)/((1+x)^3(1-x)^3); a(n)=3a(n-2)-3a(n-4)+a(n-6); a(n)=-(n^2+3n-1)/4-(n^2+n-3)(-1)^n/4. %K A110326 easy,sign %O A110326 0,3 %A A110326 _Paul Barry_, Jul 20 2005