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 A133012 #2 Mar 30 2012 17:33:49 %S A133012 2,4,8,10,12,14,16,18,20,22,24,26,30,32,34,36,38,40,42,44,46,48,50,52, %T A133012 54,56,58,60,62,64,66,68,70,72,74,76,78,80,82,84,86,88,90,92,94,96,98, %U A133012 100,102,104,106,108,110,112,114,116,118 %N A133012 Even imperfect numbers. %Y A133012 Cf. A005843, A014445, A014494. Imperfect numbers: A132999. %K A133012 easy,nonn %O A133012 1,1 %A A133012 _Omar E. Pol_, Oct 20 2007