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 A082704 #27 Feb 01 2023 21:24:40 %S A082704 3,13,15,31,105,127,343,601,9825 %N A082704 Numbers k such that (28*10^(k-1) + 17)/9 is a depression prime. %C A082704 Prime versus probable prime status and proofs are given in the author's table. %C A082704 a(10) > 2^16. - _Lucas A. Brown_, Apr 18 2021 %C A082704 a(10) > 2*10^5. - _Tyler Busby_, Feb 01 2023 %D A082704 C. Caldwell and H. Dubner, "Journal of Recreational Mathematics", Volume 28, No. 1, 1996-97, pp. 1-9. %H A082704 Patrick De Geest, <a href="http://www.worldofnumbers.com/deplat.htm#pdp313">PDP Reference Table - 313</a>. %H A082704 Makoto Kamada, <a href="https://stdkmd.net/nrr/3/31113.htm#prime">Prime numbers of the form 311...113</a>. %H A082704 <a href="/index/Pri#Pri_rep">Index entries for primes involving repunits</a>. %F A082704 a(n) = A056251(n) + 2. %e A082704 k=15 -> (28*10^(15-1) + 17)/9 = 311111111111113. %Y A082704 Cf. A082697-A082720, A056251, A068650. %K A082704 nonn,base,more %O A082704 1,1 %A A082704 _Patrick De Geest_, Apr 13 2003 %E A082704 Edited by _Ray Chandler_, Nov 04 2014