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 A106403 #3 Mar 30 2012 16:50:13 %S A106403 3,15,23,27,35,39,47,59 %N A106403 Primitive exponents of the Weyl group W(E_8). %D A106403 C. Chevalley, The Betti numbers of the exceptional Lie groups, pp. 21-24 of Proc. Internat Congress Math., Cambridge 1950, Amer. Math. Soc., 1952. %F A106403 Equals 2*A005776(n) + 1. %Y A106403 Cf. A106373, A106374, A106403, A005556, A005763. %K A106403 nonn,fini,full %O A106403 1,1 %A A106403 _N. J. A. Sloane_, May 30 2005