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 A088423 #13 May 29 2021 05:59:51 %S A088423 2,1,4,2,1,2,1,1,3,2,1,1,2,1,5,2,1,3,1,1,2,1,1,3,2,1,1,2,1,6,2,1,1,2, %T A088423 1,2,1,1,3,1,1,1,2,1,4,2,1,2,2,1,2,1,1,1,1,1,1,2,1,3,1,1,4,2,1,1,1,1, %U A088423 2,2,1,1,2,1,1,2,1,2,1,1,2,1,1,3,2,1,1,1,1,2,2,1,4,2,1,1,1,1,1,2 %N A088423 a(n) is the number of primes in arithmetic progression starting with 11 and with d = 2n. %C A088423 Arithmetic progression is stopped when next term is not prime. E.g., for n=3, a=4, that is 11,17,23,29 are prime, while next term, 35, is not prime. %H A088423 Michael De Vlieger, <a href="/A088423/b088423.txt">Table of n, a(n) for n = 1..10000</a> %t A088423 bb={}; Do[s=1; Do[If[PrimeQ[11+k*d], s=s+1, bb={bb, s}; Break[]], {k, 10}], {d, 2, 200, 2}]; Flatten[bb] %o A088423 (PARI) a(n) = my(p=11, x=p+2*n, i=1); while(1, if(ispseudoprime(x), i++; x=x+2*n, return(i))) \\ _Felix Fröhlich_, May 28 2021 %Y A088423 Cf. A088420, A088421, A088422, A088424, A088425, A088426, A088427, A088428, A088429. %K A088423 easy,nonn %O A088423 1,1 %A A088423 _Zak Seidov_, Sep 29 2003