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 A121386 #8 Jun 11 2014 21:28:47
%S A121386 2,4,6,10,14,20,16,6,36,8,44,10,8,30,16,8,12,2,12,28,64,110,96,134,56,
%T A121386 44,16,2,16,74,116,188,200,180
%N A121386 Number of different two-colorings of {1,...,n} that minimize the number of monochromatic three-term arithmetic progressions that such a coloring can contain.
%C A121386 The unique (up to switching colors) sequences for n=18 and n=28 are 001001111000011011 and 0001100011111100000011100111 respectively.
%e A121386 a(3)=6 because all non-monochromatic colorings are such an example
%Y A121386 Cf. A005346, A121385.
%K A121386 nonn
%O A121386 1,1
%A A121386 _Steve Butler_, Jul 26 2006
%E A121386 Definition corrected by _Rob Pratt_, Jun 11 2014