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 A090155 #14 Dec 11 2024 15:55:29
%S A090155 7,71,73,79,733,7333,79999,733333,799999,71111111,799999999,
%T A090155 79999999999,79999999999999999999999999,
%U A090155 79999999999999999999999999999999999999999999999999
%N A090155 Primes of the form identical digits preceded by a 7.
%H A090155 Vincenzo Librandi, <a href="/A090155/b090155.txt">Table of n, a(n) for n = 1..24</a>
%t A090155 Select[ FromDigits /@ Flatten[ Table[ PadRight[{7}, i, # ] & /@ {1, 2, 3, 4, 5, 6, 7, 8, 9}, {i, 2, 50}], 1], PrimeQ[ # ] &]
%t A090155 Select[FromDigits/@Flatten[Table[PadRight[{7},i,#]&/@{1,3,7,9},{i,50}],1],PrimeQ[#]&]//Union (* _Harvey P. Dale_, Nov 22 2024 *)
%Y A090155 Subsequence of A030096 and of A030291. Apart from the first term, a subsequence of A235154.
%K A090155 nonn,base
%O A090155 1,1
%A A090155 _Robert G. Wilson v_, Nov 22 2003