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 A208363 #37 Jun 24 2013 07:44:03 %S A208363 10000500001,10000900001,10001610001,10002220001,10002520001, %T A208363 10003630001,10006560001,10008180001,10009290001,10013031001, %U A208363 10013131001,10014741001,10016961001,10021512001 %N A208363 "3-ply" palindromic primes. %C A208363 From the Ribenboim book: palindromic primes whose length is a palindromic prime whose length is a palindromic prime whose length is NOT a palindromic prime. %D A208363 Paulo Ribenboim, The New Book of Prime Number Records, Springer-Verlag New York Inc., 1996, pages 160-161. %H A208363 Alvin Hoover Belt, <a href="/A208363/b208363.txt">Table of n, a(n) for n = 1..100</a> %e A208363 a(42042) = 99999199999, a(42043) = 10^100 + 3030*10^48 + 1. [_Charles R Greathouse IV_, Feb 26 2012] %Y A208363 Cf. A002385, A208362 (number of digits of these numbers). %K A208363 nonn,base %O A208363 1,1 %A A208363 _Alvin Hoover Belt_, Feb 25 2012