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 A099558 #3 Mar 30 2012 18:36:43 %S A099558 1,1,2,3,4,6,9,14,22,34,52,79,120,183,280,429,657,1005,1536,2347,3587, %T A099558 5484,8386,12824,19609,29981,45837,70079,107145,163820,250476,382969, %U A099558 585541,895258,1368795,2092808,3199790,4892313,7480094,11436670 %N A099558 Antidiagonal sums of the triangle A099557. %F A099558 G.f.: (1-x+x^2)/((1-x)^2-x^5). %o A099558 (PARI) a(n)=polcoeff((1-x+x^2)/((1-x)^2-x^5)+x*O(x^n),n) %Y A099558 Cf. A099557. %K A099558 nonn %O A099558 0,3 %A A099558 _Paul D. Hanna_, Oct 22 2004