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 A138043 #2 Mar 31 2012 10:26:06 %S A138043 345,51213,72425,81517,94041,116061,123537,166365,202129,284553, %T A138043 335665,367785,398089,485573,657297,2099101,6091109,15112113,17144145, %U A138043 19180181,21220221,23264265,24143145,25312313,28195197,29420421,31480481 %N A138043 Concatenation of primitive Pythagorean triangles, sorted. %H A138043 P. Alfeld, <a href="http://www.math.utah.edu/~alfeld/teaching/ptt.html">Pythagorean Triples</a> %Y A138043 Cf. A020884. %K A138043 nonn,base %O A138043 1,1 %A A138043 _Lekraj Beedassy_, Mar 02 2008