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 A127004 #7 Dec 30 2024 12:54:19
%S A127004 3,13,103,1013,10007,100003,1000003,10000019,100000007,1000000007,
%T A127004 10000000019,100000000003,1000000000061,10000000000037,
%U A127004 100000000000031,1000000000000037,10000000000000061,100000000000000003,1000000000000000003,10000000000000000097
%N A127004 Primes p+10^n arising in A127003.
%C A127004 Equivalently, smallest prime q such that q-10^n is also prime.
%t A127004 s={}; Do[p=0; Until[PrimeQ[q=Prime[p]+10^n], p++]; AppendTo[s, q], {n, 0,20}]; s (* _James C. McMahon_, Dec 30 2024 *)
%Y A127004 Cf. A127003, A056208.
%K A127004 nonn
%O A127004 1,1
%A A127004 _Rick L. Shepherd_, Jan 01 2007
%E A127004 a(18)-a(19) from _James C. McMahon_, Dec 30 2024