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 A337084 #31 Sep 21 2020 12:12:05
%S A337084 1,0,5,0,5,2,5,0,5,1,1,1,1,1,1,1,1,1,1,0,1,9,5,0,5,2,5,6,5,5,1,0,5,0,
%T A337084 4,2,4,0,5,0,1,0,5,3,3,2,5,8,5,5,1,0,5,7,5,2,5,0,5,2,1,2,2,2,5,2,5,7,
%U A337084 5,5,1,0,5,0,5,2,3,3,3,0,1,7
%N A337084 a(n) is the smallest nonzero digit d whose product d*n will contain the digit d, or 0 if no such digit exists.
%C A337084 a(n) = 1 for all numbers that contain the digit 1.
%C A337084 For all numbers with 6 followed by a digit in the 0-4 interval, a(n) is 1 or 2.
%C A337084 For all numbers with an odd digit followed by a 0, a(n) is in the 1-5 interval.
%e A337084 a(22) = 9 because none of 22*1 to 22*8 contain the digit that we multiplied 22 by to get the product, but 22*9 = 198 which contains the digit 9.
%t A337084 a[n_] := Module[{d = 1}, While[d < 10 && ! MemberQ[IntegerDigits[n*d], d], d++]; If[d < 10, d, 0]]; Array[a, 100] (* _Amiram Eldar_, Aug 15 2020 *)
%o A337084 (PARI) a(n) = {for (d=1, 9, if (#select(x->(x==d), digits(n*d)), return (d));); return (0);} \\ _Michel Marcus_, Sep 13 2020
%Y A337084 Indices of 0's give A296606.
%Y A337084 Indices of 1's give A011531.
%K A337084 nonn,base
%O A337084 1,3
%A A337084 _J. Lowell_, Aug 14 2020