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 A088424 #4 Mar 30 2012 17:26:10 %S A088424 1,2,2,1,2,1,1,2,2,1,1,3,1,2,4,1,2,1,1,2,1,1,2,4,1,1,2,1,2,2,1,1,2,1, %T A088424 2,1,1,2,1,1,1,3,1,2,6,1,2,2,1,2,1,1,1,1,1,1,3,1,2,1,1,2,2,1,1,1,1,2, %U A088424 2,1,1,2,1,1,5,1,2,1,1,2,1,1,2,3,1,1,1,1,2,3,1,2,2,1,1,1,1,1,4,1 %N A088424 Number of primes in arithmetic progression starting with 13 and with d=2n. %C A088424 Arithmetic progression is stopped when next term is not prime. E.g. for n=15, a=4, that is 13,43,73,103 are prime, while next term, 133, is not prime. %t A088424 bb={}; Do[s=1; Do[If[PrimeQ[13+k*d], s=s+1, bb={bb, s}; Break[]], {k, 10}], {d, 2, 200, 2}]; Flatten[bb] %Y A088424 Cf. A088420, A088421, A088422, A088423, A088425, A088426, A088427, A088428, A088429. %K A088424 easy,nonn %O A088424 1,2 %A A088424 _Zak Seidov_, Sep 29 2003