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 A073897 #6 Oct 29 2015 18:33:21 %S A073897 1,3,5,2,7,4,9,6,8,10,11,12,13,14,16,18,15,20,17,22,24,26,19,28,30,32, %T A073897 34,36,21,38,23,40,42,44,46,48,25,50,52,54,27,56,29,58,60,62,31,64,66, %U A073897 68,70,72,33,74,76,78,80,82,35,84,37,86,88,90,92,94,39 %N A073897 a(1) = 1, a(n) = smallest odd or even number not occurring earlier according as n is prime or composite. %H A073897 Alois P. Heinz, <a href="/A073897/b073897.txt">Table of n, a(n) for n = 1..10000</a> %Y A073897 Cf. A073898. %K A073897 nonn %O A073897 1,2 %A A073897 _Amarnath Murthy_, Aug 18 2002 %E A073897 More terms from _Alois P. Heinz_, Oct 29 2015