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 A262658 #4 Oct 31 2015 15:11:26
%S A262658 1,107,10357,12037097,32227045657,1582035465299,3799607961594979,
%T A262658 5213093566867710049,611235349109773213549,32441088456711675411793,
%U A262658 2527020301920681532766561,2174903961247108881101117191,7682944139414403968828307261263
%N A262658 Base-10 representation of 1 and the primes at A262657.
%H A262658 Clark Kimberling, <a href="/A262658/b262658.txt">Table of n, a(n) for n = 1..300</a>
%e A262658 n A262657(n) base-10 representation
%e A262658 1 1 1
%e A262658 2 21 107
%e A262658 3 42124 10357
%t A262658 s = {1}; base = 7; z = 20; Do[NestWhile[# + 1 &, 1, ! PrimeQ[tmp = FromDigits[Join[#, IntegerDigits[Last[s]], Reverse[#]] &[IntegerDigits[#, base]], base]] &];
%t A262658 AppendTo[s, FromDigits[IntegerDigits[tmp, base]]], {z}]; s (* A262657 *)
%t A262658 Map[FromDigits[ToString[#], base] &, s] (* A262658 *)
%t A262658 (* _Peter J. C. Moses_, Sep 01 2015 *)
%Y A262658 Cf. A262657.
%K A262658 nonn,easy,base
%O A262658 1,2
%A A262658 _Clark Kimberling_, Oct 27 2015