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 A029972 #13 Aug 11 2024 14:41:30
%S A029972 2,3,5,17,29,59,257,373,409,461,509,787,839,887,907,991,4289,4561,
%T A029972 5189,5669,5861,6133,6217,6553,6761,7309,7517,7789,7853,12899,13171,
%U A029972 13591,14327,14347,14411,14683,14747,14891,15083,15227,15439,15647
%N A029972 Palindromic primes in base 4.
%H A029972 John Cerkan, <a href="/A029972/b029972.txt">Table of n, a(n) for n = 1..10000</a>
%H A029972 P. De Geest, <a href="https://www.worldofnumbers.com/palpri.htm">World!Of Palindromic Primes</a>
%t A029972 Do[s = RealDigits[n, 4][[1]]; If[PrimeQ[n], If[FromDigits[s] == FromDigits[Reverse[s]], Print[n]]], {n, 1, 1600}]
%t A029972 (* Second program: *)
%t A029972 Select[Prime@ Range@ 1850, PalindromeQ@ IntegerDigits[#, 4] &] (* _Michael De Vlieger_, May 14 2017, Version 10 *)
%o A029972 (PARI) isok(n) = my(d=digits(n, 4)); d == Vecrev(d); \\ _Michel Marcus_, May 14 2017
%K A029972 nonn,base
%O A029972 1,1
%A A029972 _Patrick De Geest_