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 A069572 #12 Dec 08 2018 03:20:22 %S A069572 1,21,321,2321,52321,252321,7252321,27252321,327252321,2327252321, %T A069572 12327252321,212327252321,1212327252321,21212327252321, %U A069572 321212327252321,2321212327252321,12321212327252321,212321212327252321 %N A069572 Smallest n-digit number in which the k-th digit (from the right!) is a divisor of k, greater than 1 unless k has no single-digit divisor > 1. %Y A069572 Cf. A069570, A069571. %K A069572 nonn,base %O A069572 1,2 %A A069572 _Amarnath Murthy_, Mar 24 2002 %E A069572 a(12) corrected by _Martin Ward_, Feb 12 2013