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 A105981 #4 May 17 2017 09:23:52
%S A105981 233,313,331,337,353,373,383,433,733,2333,3313,3323,3331,3343,3373,
%T A105981 3433,3533,3733,3833,5333,7333,23333,31333,33331,33343,33353,33533,
%U A105981 38333,313333,323333,331333,333233,333323,333331,333337,333383,333433,333533
%N A105981 Near-repdigit primes with 3 as repeated digit.
%H A105981 Harvey P. Dale, <a href="/A105981/b105981.txt">Table of n, a(n) for n = 1..1000</a>
%e A105981 a(2)=313 is a term because all digits are equal to 3 except one.
%t A105981 Table[Sort[Select[FromDigits/@Flatten[Permutations/@Table[PadRight[ {n}, i,3],{n,{1,2,4,5,7,8}}],1],PrimeQ]],{i,3,6}]//Flatten (* _Harvey P. Dale_, May 17 2017 *)
%K A105981 base,nonn
%O A105981 1,1
%A A105981 _Shyam Sunder Gupta_, Apr 29 2005