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 A147819 #5 Jun 13 2017 14:32:09
%S A147819 2,4,6,8,10,12,14,16,18,20,22,24,28,30,32,36,38,40,42,44,46,48,52,54,
%T A147819 58,60,62,66,68,70,72,74,78,80,82,84,88,90,96,98,100,102,104,106,108,
%U A147819 110,112,114,126,128,130,132,136,138,140,148,150,152,156,158,162
%N A147819 Nearest-neighbors of odd primes.
%H A147819 Omar E. Pol, <a href="http://www.polprimos.com">Determinacion geometrica de los numeros primos y perfectos</a>
%t A147819 #+{-1,1}&/@Prime[Range[2,60]]//Flatten//Union (* _Harvey P. Dale_, Jun 13 2017 *)
%Y A147819 Cf. A000040, A045718, A065091, A134924, A134930.
%K A147819 easy,nonn
%O A147819 1,1
%A A147819 _Omar E. Pol_, Nov 14 2008