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 A118104 #5 Feb 27 2019 09:06:08 %S A118104 2,47,67,173,229,257,877,1009,1031,1097,1163,1669,1721,1747,1877,2731, %T A118104 2791,2851,2971,3001,3061,3121,3181,3271,3301,3331,3361,3391,3407, %U A118104 3583,3631,3727,3823,3919,3967,4079,4111,4127,4159,4597,4733,4801,4903,4937 %N A118104 Primes in A118103. %C A118104 Primes are relatively scarce in A118103 because there is often a common factor between a(n) and the difference a(n)-a(n-1); if this same difference applies to the next term, it will also be composite. %H A118104 Charlie Neder, <a href="/A118104/b118104.txt">Table of n, a(n) for n = 1..1000</a> %Y A118104 Cf. A118103, A118105. %K A118104 nonn %O A118104 1,1 %A A118104 _Franklin T. Adams-Watters_, Apr 12 2006