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 A174884 #11 May 21 2022 14:03:22
%S A174884 11,101,191,919,11411,19991,91019,94049,94949,1114111,1190911,1409041,
%T A174884 1411141,1444441,1490941,1909091,1941491,9049409,9091909,9109019,
%U A174884 9110119,9149419,9199919,9400049,9414149,9419149,9440449,9919199
%N A174884 Palindromic primes using only (decimal) square digits 0,1,4,9.
%C A174884 Four decimal square digits: 0 = 0^2, 1 = 1^2, 4 = 2^2, 9 = 3^2
%C A174884 With the exception of 11 all palindromic primes have an odd number of digits
%D A174884 Roland Sprague, Unterhaltsame Mathematik, neue Probleme, ueberraschende Loesungen, Vieweg, Braunschweig, 1961
%D A174884 David Wells, The Penguin Dictionary of Curious and Interesting Numbers, Penguin Books: London, 1986.
%H A174884 Chai Wah Wu, <a href="/A174884/b174884.txt">Table of n, a(n) for n = 1..10000</a>
%e A174884 11 = prime(5) = palprime(5), 1st term of sequence.
%e A174884 101 = prime(26) = palprime(6), 2nd term of sequence.
%e A174884 Next term using only 0 and 1 is 100111001 = prime(5767473) = palprime(785).
%t A174884 Select[FromDigits/@Tuples[{0,1,4,9},7],PalindromeQ[#]&&PrimeQ[#]&] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Mar 06 2019 *)
%Y A174884 Cf. A002385, A007500, A083185, A155214.
%K A174884 base,nonn
%O A174884 1,1
%A A174884 Eva-Maria Zschorn (e-m.zschorn(AT)zaschendorf.km3.de), Apr 01 2010