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 A105977 #4 Dec 12 2015 11:25:39
%S A105977 277,577,677,727,757,773,787,797,877,977,1777,2777,7177,7477,7577,
%T A105977 7717,7727,7757,7877,47777,67777,71777,76777,77377,77477,77747,77773,
%U A105977 77797,77977,79777,97777,727777,773777,775777,777277,777677,777737,777787
%N A105977 Near-repdigit primes with 7 as repeated digit.
%H A105977 Harvey P. Dale, <a href="/A105977/b105977.txt">Table of n, a(n) for n = 1..1000</a>
%e A105977 a(2)=577 is a term because all digits are equal to 7 except one.
%t A105977 Select[Union[FromDigits/@(Flatten[Permutations/@Flatten[ Table[ PadRight[ {n},i,7],{n,9},{i,3,6}],1],1])],PrimeQ] (* _Harvey P. Dale_, Dec 12 2015 *)
%K A105977 base,nonn
%O A105977 1,1
%A A105977 _Shyam Sunder Gupta_, Apr 29 2005