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 A204047 #20 Mar 30 2012 18:39:53 %S A204047 1023456798,1023456789,1052674893,1053274689,13047685942,36492195078, %T A204047 153846076923,251793406487,0,1189658042735,5128207435967, %U A204047 3846154076923,125583660720493,125583660493072,180106284973592,201062849735918 %N A204047 Smallest number that is n-persistent but not (n+1)-persistent, i.e., k, 2k, ..., nk, but not (n+1)k, are pandigital in the sense of A171102; 0 if such a number does not exist. %C A204047 a(9) is 0 because any 9-persistent number is also 10-persistent. Indeed, if n is pandigital, 10*n is pandigital as well. %C A204047 In the same way, a(10m-1)=0 for all m>0 since if kn is pandigital for all k=1,...,10m-1, then mn is pandigital and so is 10mn. - M. F. Hasler, Jan 10 2012 %D A204047 Ross Honsberger, More Mathematical Morsels, Mathematical Association of America, 1991, pages 15-18. %e A204047 k=36492195078 is the smallest number such that k, 2k, 3k, 4k, 5k, and 6k, each contain all ten digits, but 7k=255445365546 contains only five of the ten, so a(6)= 36492195078. %Y A204047 Cf. A051264, A051018, A051019, A051020, A204096, A204097. %K A204047 nonn,base %O A204047 1,1 %A A204047 _Hans Havermann_, Jan 09 2012 %E A204047 a(7)-a(16) from _Giovanni Resta_, Jan 10 2012