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 A049745 #4 Mar 30 2012 18:56:56 %S A049745 13,21,25,45,69,97,129,177,221,277,333,401,473,553,633,725,821,933, %T A049745 1041,1153,1273,1405,1541,1685,1829,1993,2145,2313,2477,2661,2845, %U A049745 3041,3241,3433,3657,3869,4085,4317,4545,4809,5049,5297 %N A049745 a(n)=T(n,2), array T as in A049735. %K A049745 nonn %O A049745 0,1 %A A049745 _Clark Kimberling_