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 A206242 #25 Jul 11 2021 05:19:35 %S A206242 2,3,6,5,20,7,28,24,72,11,99,13,104,126,120,17,272,19,304,180,336,23, %T A206242 414,120,400,234,432,29,783,31,496,864,1056,850,1120,37,1184,1026, %U A206242 1248,41,1476,43,1376,1188,1440,47,1692,336,1960,1350,1632,53,2544,1350 %N A206242 a(n) is the least number j such that, for any integer k > 0, the base-n representations of the numbers k, 2k, ..., j*k together include every base-n digit. %H A206242 David W. Wilson, <a href="/A206242/b206242.txt">Table of n, a(n) for n = 2..10000</a> %F A206242 a(n) = n if n prime; (n-1)*A079277(n) otherwise. %e A206242 In base 7, for any k > 0, the numbers k,2k,...,7k together include every base-7 digit. k = 1 is the smallest number for which we need to go up to 7k to encounter digit 0 in 7k = 7 = 10_7. Hence a(7) = 7 and A206243(7) = 1. %e A206242 In base 10, for any k > 0, the numbers k,2k,...,72k together include every base-10 digit. k = 125 is the smallest number for which we need to go up to 72k = 9000 to encounter digit 9. Hence a(10) = 72 and A206243(7) = 125. %Y A206242 Cf. A079277, A206243 (smallest value of k for which a(n) is required). %K A206242 nonn,base %O A206242 2,1 %A A206242 _David W. Wilson_, Feb 05 2012