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 A117703 #6 Feb 16 2025 08:33:00 %S A117703 2,3,5,7,131,151,212,232,272,414,454,515,737,757,838,858,878,10501, %T A117703 10701,11711,12521,13531,13731,15151,15551,16161,17371,18181,18781 %N A117703 Palindromic primes in base 9 (written in base 9). %H A117703 Eric Weisstein: <a href="https://mathworld.wolfram.com/PalindromicPrime.html">Palindromic Prime</a>. %Y A117703 Cf. A029977. %K A117703 nonn,base %O A117703 1,1 %A A117703 _Martin Renner_, Apr 13 2006