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 A126738 #9 Aug 15 2019 16:51:08 %S A126738 0,0,0,1,3,26,282,5009,149551,7694428,667036310 %N A126738 Number of connected graphs on n nodes with chromatic number 4. %H A126738 Keith M. Briggs, <a href="http://keithbriggs.info/cgt.html">Combinatorial Graph Theory</a> %Y A126738 A diagonal of triangle in A126736. %K A126738 nonn %O A126738 1,5 %A A126738 _N. J. A. Sloane_, Feb 16 2007 %E A126738 a(11) from _Michael Sollami_, Jan 29 2012