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 A117784 #11 Feb 16 2025 08:33:00 %S A117784 3,0,6,0,41,0,154,0,931,0,4951,0,29932,0,180914,0,1089138,0,6823068,0, %T A117784 43644808,0,274927477,0 %N A117784 Total number of palindromic primes in base 7 with n digits. %C A117784 Every palindrome with an even number of digits is divisible by 11 (in base 7) and therefore is composite (not prime). Hence there is no palindromic prime with an even number of digits. %H A117784 Eric Weisstein: <a href="https://mathworld.wolfram.com/PalindromicPrime.html">Palindromic Prime</a>. %Y A117784 Cf. A029975, A117702. %K A117784 nonn,base %O A117784 1,1 %A A117784 _Martin Renner_, Apr 15 2006 %E A117784 a(9)-a(24) from _Chai Wah Wu_, Dec 26 2015