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 A191331 #8 Jan 17 2018 13:16:42 %S A191331 2,6,12,16,18,22,28,32,34,38,42,44,48,54,58,60,64,70,74,80,84,86,90, %T A191331 96,100,102,106,110,112,116,122,126,128,132,138,142,148,152,154,158, %U A191331 164,168,170,174,180,184,190,194,196,200,206,210,212,216,220,222,226,232,236,238,242,248,252,258,262,264,268,274,278,280,284,288 %N A191331 Positions of 2 in A191329. %C A191331 A191331=2*A005652. %e A191331 A191329=(1,2,1,0,1,2,1,0,1,0,1,2,...), so that %e A191331 a(1)=2, a(2)=6, a(3)=12,... %t A191331 (See A191329.) %Y A191331 Cf. A191329, A191330, A191332, A191333. %K A191331 nonn %O A191331 1,1 %A A191331 _Clark Kimberling_, May 31 2011