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 A172069 #11 Nov 11 2013 14:17:46 %S A172069 1,1,2,2,2,2,2,1,1,2,1,2,1,1,2,1,1,0,1,1,0,0,0,1,2,0,2,1,0,1,0,1,1,0, %T A172069 1,1,0,0,0,0,0,0,0,1,0,1,0,1,1,0,1,0,0,1,1,1,0,1,1,0,0,0,1,1,1,0,0,0, %U A172069 2,1,0,1,0,1,0,0,0,1,1,1,0,1,0,1,0,0,1,0,0,0,1,0,1,1,0,1,1,1,0,0,0,1,1,2,0,0 %N A172069 The number of primes adjacent to A129912(n): 0, 1 or 2. %H A172069 Bill McEachen, <a href="/A172069/b172069.txt">Table of n, a(n) for n = 1..282</a> %e A172069 Both 415799 and 415801 are prime, so the entry at 415800 (n=27) is a 2 (twin primes). %e A172069 Neither 27719 nor 27721 are prime, so the entry at 27720 (n=18) is a 0. %Y A172069 Cf. A129912. %K A172069 easy,nonn %O A172069 1,3 %A A172069 _Bill McEachen_, Jan 24 2010 %E A172069 Offset corrected and sequence extended by _R. J. Mathar_, Feb 19 2010 %E A172069 a(1) added by _T. D. Noe_, Nov 11 2013