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 A243709 #14 Dec 24 2014 01:08:36 %S A243709 6,10,14,18,22,30,46 %N A243709 Coxeter numbers of the D-type Niemeier root systems. %C A243709 These are exactly the even integers 2n such that the group Gamma_0(2n)+n has genus zero. %H A243709 Miranda C. N. Cheng, John F. R. Duncan and Jeffrey A. Harvey, <a href="http://www.resmathsci.com/content/1/1/3">Umbral moonshine and the Niemeier lattices</a>, Research in the Mathematical Sciences, 2014, 1:3. See Eq. (23). %F A243709 a(n) = 2*A133848(n+11). - _Omar E. Pol_, Dec 20 2014 %Y A243709 Cf. A091401. %K A243709 nonn,fini,full %O A243709 1,1 %A A243709 _N. J. A. Sloane_, Jun 19 2014