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 A082703 #20 Nov 09 2019 04:16:59 %S A082703 3,5,9,41,87,201,731,1461,23673,28631 %N A082703 Numbers k such that (18*10^(k-1) - 81)/9 is a plateau prime. %C A082703 Prime versus probable prime status and proofs are given in the author's table. %D A082703 C. Caldwell and H. Dubner, "Journal of Recreational Mathematics", Volume 28, No. 1, 1996-97, pp. 1-9. %H A082703 Patrick De Geest, <a href="http://www.worldofnumbers.com/deplat.htm#pdp191">PDP Reference Table - 191</a>. %H A082703 Makoto Kamada, <a href="https://stdkmd.net/nrr/1/19991.htm#prime">Prime numbers of the form 199...991</a>. %H A082703 <a href="/index/Pri#Pri_rep">Index entries for primes involving repunits</a>. %F A082703 a(n) = A056250(n+1) + 2. %e A082703 k=9 -> (18*10^(9-1) - 81)/9 = 199999991. %Y A082703 Cf. A082697-A082720, A056250, A068649. %K A082703 nonn,base,more %O A082703 1,1 %A A082703 _Patrick De Geest_, Apr 13 2003 %E A082703 More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008 %E A082703 Edited by _Ray Chandler_, Nov 04 2014