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 A093162 #20 Dec 26 2022 16:30:17
%S A093162 3,23,223,22222223,22222222223,222222222222222222222222222222222223
%N A093162 Primes of the form 20*R_k + 3, where R_k is the repunit (A002275) of length k.
%C A093162 The next term (a(7)) has 95 digits. - _Harvey P. Dale_, Dec 26 2022
%H A093162 Makoto Kamada, <a href="https://stdkmd.net/nrr/2/22223.htm#prime">Prime numbers of the form 22...223</a>.
%H A093162 <a href="/index/Pri#Pri_rep">Index entries for primes involving repunits</a>
%F A093162 a(n) = (20*10^A056656(n) + 7)/9 = (2*10^A096506(n) + 7)/9.
%t A093162 Select[Table[FromDigits[PadLeft[{3},n,2]],{n,40}],PrimeQ] (* _Harvey P. Dale_, Dec 26 2022 *)
%Y A093162 Cf. A002275, A056656 (corresponding k, and count of digits 2 in a(n)), A096506.
%K A093162 nonn
%O A093162 1,1
%A A093162 _Rick L. Shepherd_, Mar 26 2004
%E A093162 Edited by _Ray Chandler_, Feb 27 2012