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 A108493 #27 Jan 17 2019 13:44:08 %S A108493 2,7,10,11,17,19,39,49,50,61,95,106,187,196,849,889,6436,7370,14446, %T A108493 19647,34399,39922,81297,84305 %N A108493 Integers n such that 10^n-57 is prime. %C A108493 Numbers corresponding to terms 849 and 889 are certified primes. (Primo 2.2.0 beta) - _Ryan Propper_, Jul 13 2005 %C A108493 No additional terms <100000. %C A108493 See Kamada link - primecount.txt for terms, primesize.txt for discovery details including probable or proved primes - search on "99943". %H A108493 Makoto Kamada, <a href="https://stdkmd.net/nrr/prime/">List of near-repdigit-related prime numbers</a>. %H A108493 <a href="/index/Pri#Pri_rep">Index entries for primes involving repunits</a>. %e A108493 n = 7 is a member because: 10^7-57 = 10000000-57 = 9999943, which is prime. %Y A108493 Cf. A089675, A095714, A092767, A108327, A108328, A108329, A108330, A108331, A108332, A177417. %K A108493 more,nonn %O A108493 1,1 %A A108493 Julien Peter Benney (jpbenney(AT)ftml.net), Jul 06 2005 %E A108493 a(17)-a(19) from Kamada data by _Robert Price_, Dec 10 2010 %E A108493 a(20) from Kamada data by _Robert Price_, Dec 14 2010 %E A108493 a(21)-a(22) from _Robert Price_, Dec 15 2010 %E A108493 Edited by _Ray Chandler_, Dec 23 2010 %E A108493 a(23-24)=81297,84305 from _Robert Price_, May 29 2011