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 A049648 #4 Mar 30 2012 18:56:55 %S A049648 1,4,7,11,17,23,31,41,51,61,75,89,105,123,137,153,177,199,223,249,269, %T A049648 291,323,353,381,413,443,473,513,549,587,633,669,705,745,781,829,883, %U A049648 925,965,1021,1073,1127,1189,1233,1279,1347,1409,1467,1529,1581,1637 %N A049648 T(n,n+1), array T as in A049687 and T(2n,2n+2), array T given by A049639. %K A049648 nonn %O A049648 0,2 %A A049648 _Clark Kimberling_ %E A049648 More terms from Michael Somos