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 A046399 #33 Feb 09 2023 09:58:45
%S A046399 1,2,6,66,858,6006,222222,22444422,244868442,6434774346,438024420834,
%T A046399 50146955964105,2415957997595142,495677121121776594,
%U A046399 22181673755737618122,5521159517777159511255,477552751050050157255774
%N A046399 Smallest squarefree palindrome with exactly n distinct prime factors.
%C A046399 Initial terms of sequences A046392-A046398.
%D A046399 J.-P. Delahaye, Merveilleux nombres premiers ("Amazing primes"), p. 315, Pour la Science, Paris 2000.
%e A046399 a(4) = 858 = 2*3*11*13.
%t A046399 r[n_] := FromDigits[Reverse[IntegerDigits[n]]]; Do[k = 1; While[r[k] != k || !SquareFreeQ[k] || Length[Select[Divisors[k], PrimeQ]] != n, k++ ]; Print[k], {n, 0, 30}] (* _Ryan Propper_, Sep 16 2005 *)
%Y A046399 Cf. A046385, A076886.
%Y A046399 Cf. A046392, A046393, A046394, A046395, A046396, A046397, A046398.
%K A046399 nonn,base,hard,more
%O A046399 0,2
%A A046399 _Patrick De Geest_, Jun 15 1998
%E A046399 Edited by _N. J. A. Sloane_, Dec 06 2008 at the suggestion of _R. J. Mathar_
%E A046399 a(10)-a(13) from _Donovan Johnson_, Oct 03 2011
%E A046399 a(14)-a(15) from _David A. Corneth_, Oct 03 2020
%E A046399 a(15) corrected by _Daniel Suteu_, Feb 05 2023
%E A046399 a(16) from _Michael S. Branicky_, Feb 08 2023