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 A031931 #16 Jun 24 2022 17:17:43 %S A031931 211,223,479,521,631,673,809,1009,1213,1249,1319,1471,1511,1523,1543, %T A031931 1721,1801,1823,1901,2081,2111,2309,2411,2459,2591,2633,2789,2939, %U A031931 3061,3079,3181,3203,3271,3343,3359,3511,3571,3671,3943,4001,4091,4111,4409,4421 %N A031931 Upper prime of a difference of 12 between consecutive primes. %H A031931 Harvey P. Dale, <a href="/A031931/b031931.txt">Table of n, a(n) for n = 1..1000</a> %H A031931 <a href="/index/Pri#gaps">Index entries for primes, gaps between</a> %t A031931 Select[Partition[Prime[Range[700]],2,1],#[[2]]-#[[1]]==12&][[All,2]] (* _Harvey P. Dale_, Dec 28 2018 *) %o A031931 (PARI) isok(p) = isprime(p) && (p-precprime(p-1) == 12); \\ _Michel Marcus_, Jun 24 2022 %Y A031931 Cf. A031925 (difference of 6). %K A031931 nonn %O A031931 1,1 %A A031931 _Jeff Burch_ %E A031931 Corrected and extended by _Harvey P. Dale_, Dec 28 2018