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 A048150 #4 Mar 30 2012 18:56:54 %S A048150 1,4,9,20,31,48,65,86,113,140,173,206,239,286,327,378,425,478,533,590, %T A048150 659,722,793,862,933,1020,1099,1184,1271,1360,1455,1550,1655,1758, %U A048150 1865,1976,2079,2202,2319,2448,2569,2694,2827,2960 %N A048150 a(n)=number of numbers h^2+k^2 that are <=2n^2; equivalently, a(n)=T(n,n), array T as in A048149. %K A048150 nonn %O A048150 0,2 %A A048150 _Clark Kimberling_