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 A272881 #13 Nov 24 2019 21:50:08 %S A272881 1,2,4,4,7,8,8,8,13,16,16,16,16,16,16,16,31,32,32,32,32,32,32,32,32, %T A272881 32,32,32,32,32,32,32,61,64,64,64,64,64,64,64,64,64,64,64,64,64,64,64, %U A272881 64,64,64,64,64,64,64,64,64,64,64,64,64,64,64,64,127,128,128,128,128,128,128,128,128,128,128,128,128,128,128,128,128,128,128 %N A272881 Discriminator of the evil numbers (A001969). %C A272881 The discriminator of a sequence is the least positive integer k such that the first n terms of the sequence are pairwise distinct, modulo k. %C A272881 The discriminator of this sequence is given by 2^(i+1) - 3 if n = 2^i + 1 for odd i > 2; 2^(i+1) - 1 if n = 2^i + 1 for even i >= 2; and 2^(ceiling(log_2(n))) otherwise. %H A272881 Arnold, L. K.; Benkoski, S. J.; and McCabe, B. J.; <a href="http://www.jstor.org/stable/2323651">The discriminator (a simple application of Bertrand's postulate)</a>. Amer. Math. Monthly 92 (1985), 275-277. %H A272881 Sajed Haque, Jeffrey Shallit, <a href="http://arxiv.org/abs/1605.00092">Discriminators and k-Regular Sequences</a>, arXiv:1605.00092 [cs.DM], 2016. %Y A272881 Cf. A001969. %K A272881 nonn %O A272881 1,2 %A A272881 _Jeffrey Shallit_, May 08 2016