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 A046450 #17 Dec 06 2014 11:43:17
%S A046450 4,8,9,121,343,1331,10001,10201,14641,36763,1030301,1037301,1226221,
%T A046450 9396939,104060401,12467976421,14432823441,93969696939,119092290911,
%U A046450 1030507050301,1120237320211,1225559555221,1234469644321,1334459544331,100330272033001,101222252222101
%N A046450 Concatenation of prime factors of palindromic composite is a palindrome.
%e A046450 E.g., 14432823441 = 3 * 3 * 281 * 313 * 18233 -> 3328131318233 is palindromic.
%t A046450 d[n_] := IntegerDigits[n]; co[n_, k_] := Nest[Flatten[d[{#, n}]] &, n, k - 1]; t = {}; Do[If[! PrimeQ[n] && Reverse[x = d[n]] == x && Reverse[y = Flatten[d[co @@@ FactorInteger[n]]]] == y, AppendTo[t, n]], {n, 2, 10^7}]; t (* _Jayanta Basu_, Jun 24 2013 *)
%Y A046450 Cf. A046447, A046448, A046449.
%K A046450 nonn,base
%O A046450 1,1
%A A046450 _Patrick De Geest_, Jul 15 1998
%E A046450 Corrected by _Charles R Greathouse IV_, Apr 23 2010
%E A046450 a(18)-a(24) from _Donovan Johnson_, May 03 2010
%E A046450 a(25)-a(26) from _Donovan Johnson_, Aug 09 2011