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 A217918 #7 Mar 06 2013 00:31:18 %S A217918 1,4,11,29,46,121,172,191,254,1276,1432,1654,2416,2486,5254,9181,9592, %T A217918 10012,10441,11629,12881,14029,14197,16472,20707,22367,23872,24532, %U A217918 24977,26336,26797,27496,28681,29162,37951,38227,40756 %N A217918 Positions of 2 in sequence A217916. %F A217918 Involves triangular-indexed twin primes: %F A217918 prime(a(n)) - prime(a(n)-1) = 2 for n>1 with a(1)=1. %Y A217918 Cf. A217916, A217919. %K A217918 nonn %O A217918 1,2 %A A217918 _Paul D. Hanna_, Mar 04 2013