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 A046456 #7 Oct 27 2019 00:34:12 %S A046456 128,2187,78125,496875,823543,1908795,3680733,6280989,11447205, %T A046456 11639595,14480427,15839397,15988245,17998875,19165069,19487171, %U A046456 22073667,22444653,27340845,30830163,35277795,38975433,44183867 %N A046456 Concatenation of the 7 prime factors of composite a(n) is a palindrome. %e A046456 17998875 = 3 * 3 * 3 * 5 * 5 * 5 * 5333 -> 3335555333 is palindromic. %Y A046456 Cf. A046447. %K A046456 nonn,base %O A046456 1,1 %A A046456 _Patrick De Geest_, Jul 15 1998 %E A046456 Edited by _Charles R Greathouse IV_, Apr 28 2010