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 A082720 #13 Nov 11 2019 21:46:46 %S A082720 3,5,7,9,11,13,15,17,19,21,23,29,31,33,37,41,49,53,55,59,61,65,67,69, %T A082720 73,75,83,85,87,93,95,97,101,103,105,111,113,115,117,121,127,129,141, %U A082720 157,161,171,193,201,205,209,231,247,291,323,343,351,353,361,367,401 %N A082720 Digit lengths for which there exist plateau or depression primes of the general form a*(10^m-1)/9 +- b*(10^(m-1)+1). %D A082720 C. Caldwell and H. Dubner, "Journal of Recreational Mathematics", Volume 28, No. 1, 1996-97, pp. 1-9. %H A082720 Patrick De Geest, <a href="http://www.worldofnumbers.com/pdpsorted.htm">PDP's Sorted By Length</a> %Y A082720 Cf. A082697-A082719, A077797, A077799. %K A082720 nonn,base %O A082720 0,1 %A A082720 _Patrick De Geest_, Apr 13 2003