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 A052339 #5 Mar 30 2012 17:37:10 %S A052339 1,4,12,13,42,43,73,658 %N A052339 Values of n at which record values in A052340 are reached. %C A052339 A subsequence of A050412. %Y A052339 Cf. A050412, A051914, A052333, A052334, A052340. %K A052339 nonn,hard %O A052339 1,2 %A A052339 _Christian G. Bower_, Dec 23 1999 %E A052339 659*2^n-1 is composite for n<2^17. %E A052339 One more term supplied by _David Broadhurst_, Jan 02 2000