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 A078204 #7 Dec 05 2013 19:55:56
%S A078204 1,216,32103,4321468,543217035,65432173824,7654321572835,
%T A078204 876543212074068,98765432187654312,109876543212580239340,
%U A078204 11109876543210457373921742,12111098765432151566924849880
%N A078204 Smallest multiple of the concatenation of 1 up to n that begins with the concatenation of n down to 1.
%e A078204 a(3) = 32103 = 123 * 261.
%t A078204 f[n_] := Module[{upto = FromDigits[Range[n]], downfrom = FromDigits[Reverse[Range[n]]], i = 1}, While[upto - Mod[10^i downfrom, upto] > 10^i, i++ ]; 10^i downfrom + upto - Mod[10^i downfrom, upto]]; Table[f[n], {n, 2, 9}]
%Y A078204 Cf. A078205.
%K A078204 base,nonn
%O A078204 1,2
%A A078204 _Amarnath Murthy_, Nov 22 2002
%E A078204 More terms from _Harvey P. Dale_, Dec 07 2002
%E A078204 More terms from _Sascha Kurz_, Jan 04 2003