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a(n) is the least positive multiple of n that contains at least one digit 1 in its decimal representation.
2

%I #11 Apr 09 2022 17:28:42

%S 1,10,12,12,10,12,14,16,18,10,11,12,13,14,15,16,17,18,19,100,21,110,

%T 115,120,100,104,81,112,116,120,31,128,132,102,105,108,111,114,117,

%U 120,41,126,129,132,135,138,141,144,147,100,51,104,106,108,110,112,114

%N a(n) is the least positive multiple of n that contains at least one digit 1 in its decimal representation.

%H Rémy Sigrist, <a href="/A317180/b317180.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = n * A317173(n).

%F a(n) <= A187285(n).

%e The multiples of 3 are: 3, 6, 9, 12, 15, etc.; 12 is the first one containing the digit 1, hence a(3) = 12.

%t on1[n_]:=Module[{k=1},While[DigitCount[k*n,10,1]<1,k++];k*n]; Array[on1,60] (* _Harvey P. Dale_, Apr 09 2022 *)

%o (PARI) a(n) = forstep (m=n, oo, n, if (setsearch(Set(digits(m)), 1), return (m)))

%Y Cf. A011531, A187285, A317173.

%K nonn,base

%O 1,2

%A _Rémy Sigrist_, Jul 23 2018

%E Definition clarified by _Harvey P. Dale_, Apr 09 2022