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 A065533 #11 Jun 18 2018 03:26:31
%S A065533 3,31,311,3119,31193,311951,3119533,31195343,311953441,3119534441,
%T A065533 31195344413,311953444133,3119534441393,31195344413953,
%U A065533 311953444139539,3119534441395579,31195344413955853,311953444139558593
%N A065533 a(n) is smallest prime > 10*a(n-1), a(1) = 3.
%H A065533 Harry J. Smith, <a href="/A065533/b065533.txt">Table of n, a(n) for n = 1..100</a>
%t A065533 NextPrim[n_Integer] := Block[ {k = n + 1}, While[ !PrimeQ[k], k++ ]; Return[k]]; a[1] = 3; a[n_] := NextPrim[ 10*a[n - 1]]; Table[ a[n], {n, 1, 20} ]
%t A065533 NestList[NextPrime[10#]&,3,20] (* _Harvey P. Dale_, Jul 04 2012 *)
%o A065533 (PARI) { for (n=1, 100, if (n>1, a=nextprime(10*a), a=3); write("b065533.txt", n, " ", a) ) } \\ _Harry J. Smith_, Oct 21 2009
%Y A065533 Cf. A065122.
%K A065533 nonn
%O A065533 1,1
%A A065533 _Robert G. Wilson v_, Nov 28 2001