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 A093171 #21 Jul 08 2021 06:20:43 %S A093171 7,887,8887,888887,888888887,888888888887, %T A093171 888888888888888888888888888888888888888888888888888888888888888888888887 %N A093171 Primes of the form 80*R_k + 7, where R_k is the repunit (A002275) of length k. %C A093171 Primes of the form (8*10^k - 17)/9. - _Vincenzo Librandi_, Nov 16 2010 %H A093171 Makoto Kamada, <a href="https://stdkmd.net/nrr/8/88887.htm#prime">Prime numbers of the form 88...887</a>. %H A093171 <a href="/index/Pri#Pri_rep">Index entries for primes involving repunits</a> %Y A093171 Cf. A056695 (corresponding k), A096846. %K A093171 nonn %O A093171 1,1 %A A093171 _Rick L. Shepherd_, Mar 26 2004