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 A103824 #3 Mar 30 2012 17:29:22 %S A103824 1,3,9,2,4,5,35,7,65,11,15,13,21,17,25,19,55,23,49,29,91,31,27,37,115, %T A103824 41,77,43,121,47,85,53,125,59,39,61,33,67,133,71,143,73,119,79,95,83, %U A103824 81,89,145,97,51,101,99,103,45,107,57,109,87,113,69,127,75,131,111,137 %N A103824 Choose a(n) to be the smallest number not yet used such that: a(1) = 1, a(2n) = prime, a(2n+1) = composite and partial sums are alternately composite or prime. %Y A103824 Cf. A075593, A075594, A103825. %K A103824 nonn %O A103824 1,2 %A A103824 _Ray Chandler_ Feb 16 2005 %E A103824 Definition corrected by Zak Seidov, Feb 20 2005