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 A031880 #14 Nov 15 2019 07:04:40 %S A031880 1,9,33,99,111,141,171,303,393,535,717,777,979,1441,1771,3003,3223, %T A031880 3663,5335,7447,9009,9339,9999,11011,11811,11911,12121,12321,12621, %U A031880 13531,14041,14541,14841,17671,18381,18681,19791,30303,31713,32223 %N A031880 Lucky numbers that are both palindromic and nonprime. %H A031880 Amiram Eldar, <a href="/A031880/b031880.txt">Table of n, a(n) for n = 1..5436</a> (terms below 10^9) %Y A031880 Intersection of A000959 and A032350. %K A031880 nonn,base %O A031880 1,2 %A A031880 _Patrick De Geest_ %E A031880 Name corrected by _Amiram Eldar_, Nov 15 2019