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 A283313 #8 Mar 09 2017 00:48:25 %S A283313 2,3,3,5,5,7,7,8,8,9,11,12,12,13,15,15,16,17,18,18,19,20,20,21,23,24, %T A283313 24,25,27,28,29,30,30,31,32,32,33,35,36,37,39,39,40,41,42,42,43,44,44, %U A283313 45,47,48,48,49,50,51,52,53,54,54,55,56,57,59,60,60,61,63,63,64,65,66,67,68,68,69,70,71,72 %N A283313 Smallest missing number after A283312(n) has been found. %H A283313 N. J. A. Sloane, <a href="/A283313/b283313.txt">Table of n, a(n) for n = 1..20000</a> %Y A283313 Cf. A283312. %K A283313 nonn %O A283313 1,1 %A A283313 _N. J. A. Sloane_, Mar 08 2017