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 A160812 #11 Mar 11 2014 01:34:14 %S A160812 0,0,0,0,2,0,2,0,2,2,4,0,4,2,2,2,6,2,6,2,4,4,6,0,6,6,6,4,8,2,8,4,6,6, %T A160812 6,2,10,8,8,4,10,4,10,6,6,8,10,2,10,8,10,8,12,6,10,6,10,10,12,2,12,10, %U A160812 8,8,12,8,14,10,12,8,14,4,14,12,10,10,12,8,14,6,12,14,16,6,14,14,14,10,16,6 %N A160812 a(n) = A161205(n)-A000005(n). %C A160812 It appears that a(n)= 0 if and only if n divides 24 (See also the comments in A018253). %H A160812 Omar E. Pol, <a href="http://www.polprimos.com">Determinacion geometrica de los numeros primos y perfectos</a> %H A160812 Omar E. Pol, <a href="http://www.polprimos.com/imagenespub/polprdipi.jpg">Illustration: Divisors and pi(x)</a> %F A160812 a(n) = 2*(A000196(n) - A038548(n)) = 2*A236627(n). - _Omar E. Pol_, Feb 05 2014 %Y A160812 Cf. A000005, A000720, A018253, A160811, A161205. %K A160812 easy,nonn %O A160812 1,5 %A A160812 _Omar E. Pol_, Jun 19 2009 %E A160812 Edited by _Omar E. Pol_, Aug 02 2009