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 A226066 #18 May 25 2018 13:38:24
%S A226066 1,2,3,4,5,7,8,9,10,12,13,14,15,17,18,19,20,22,23,24,25,26,29,32,33,
%T A226066 35,36,37,39,40,41,44,45,46,48,49,50,51,54,56,58,59,61,62
%N A226066 Smallest k such that n numbers can be picked in {1,...,k} with no six terms in arithmetic progression.
%D A226066 Knuth, Donald E., Satisfiability, Fascicle 6, volume 4 of The Art of Computer Programming. Addison-Wesley, 2015, pages 135 and 190, Problem 31.
%H A226066 Samuel S. Wagstaff, Jr., <a href="http://dx.doi.org/10.1090/S0025-5718-1972-0325500-5">On k-free sequences of integers</a>, Math. Comp., 26 (1972), 767-771.
%Y A226066 This sequence is to A003005 as A065825 is to A003002.
%Y A226066 Cf. A225745, A225859.
%K A226066 nonn,more
%O A226066 1,2
%A A226066 _Don Knuth_, Aug 05 2013