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 A082713 #31 Nov 10 2019 01:33:39 %S A082713 3,5,11,21,23,59,75,83,209,351,423,3813,3983,20925,23787,38853,56043, %T A082713 68505,74435 %N A082713 Numbers k such that (68*10^(k-1) + 13)/9 is a depression prime. %C A082713 Prime versus probable prime status and proofs are given in the De Geest link. %D A082713 C. Caldwell and H. Dubner, The near repdigit primes A(n-k-1)B(1)A(k), especially 9(n-k-1)8(1)9(k), Journal of Recreational Mathematics, Volume 28, No. 1, 1996-97, pp. 1-9. %H A082713 Patrick De Geest, <a href="http://www.worldofnumbers.com/deplat.htm#pdp757">PDP Reference Table - 757</a>. %H A082713 Makoto Kamada, <a href="https://stdkmd.net/nrr/7/75557.htm#prime">Prime numbers of the form 755...557</a>. %H A082713 <a href="/index/Pri#Pri_rep">Index entries for primes involving repunits</a>. %F A082713 a(n) = A056259(n) + 2. %e A082713 k=21 -> (68*10^(21-1) + 13)/9 = 755555555555555555557. %Y A082713 Cf. A082697-A082720, A056259. %K A082713 nonn,base,hard,more %O A082713 1,1 %A A082713 _Patrick De Geest_, Apr 13 2003 %E A082713 Updates from De Geest site by Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008 %E A082713 a(17)=56043 and a(18)=68505 from _Ray Chandler_, Nov 16 2010 %E A082713 a(19)=74434 from _Ray Chandler_, Nov 17 2010 %E A082713 a(19) corrected by _Patrick De Geest_, Nov 04 2014 %E A082713 Edited by _Ray Chandler_, Nov 05 2014 %E A082713 Definition rewritten by _Michel Marcus_, Oct 27 2019