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 A046331 #10 Oct 10 2019 22:54:33 %S A046331 252,272,464,616,656,696,828,848,888,2552,4004,4554,4664,4884,5445, %T A046331 5775,6006,6996,8118,8228,8778,8888,9009,18081,18981,20202,20502, %U A046331 21012,21812,22022,23432,23532,24642,25552,25652,26862,27272,27672,28182 %N A046331 Palindromes with exactly 5 prime factors (counted with multiplicity). %H A046331 Harvey P. Dale, <a href="/A046331/b046331.txt">Table of n, a(n) for n = 1..1000</a> %t A046331 Select[Range[30000],#==IntegerReverse[#]&&PrimeOmega[#]==5&] (* The program uses the IntegerReverse function from Mathematica version 10 *) (* _Harvey P. Dale_, Jul 16 2016 *) %Y A046331 Cf. A014614, A046318. %K A046331 nonn,base %O A046331 1,1 %A A046331 _Patrick De Geest_, Jun 15 1998