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 A171639 #2 Mar 30 2012 19:00:22 %S A171639 2,6,9,13,16,21,25,31,34,39,47,51,58,63,67,72,79,86,89,97,103,106,113, %T A171639 118,125,135,140,143,149,153,158,173,179,186,189,200,203,211,218,223, %U A171639 230,237,241,253,256,261,264,277,291,296 %N A171639 Sum of n-th nonprime number and n-th noncomposite number. %C A171639 a(n) = A008578(n) + A018252(n). %F A171639 a(n) = A064799(n-1) for n >= 2. %K A171639 nonn %O A171639 1,1 %A A171639 _Jaroslav Krizek_, Dec 13 2009