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%I #9 Jul 28 2018 11:13:29
%S 1,5,4,3,2,2,2,2,2,1,1,1,1,1,1,1,1,1,1,5,1,5,5,5,4,4,3,4,4,4,1,4,4,3,
%T 3,3,3,3,3,3,1,3,3,3,3,3,3,3,3,2,1,2,2,2,2,2,2,2,2,2,1,2,2,2,2,2,2,2,
%U 2,2,1,2,2,2,2,2,2,2,2,2,1,2,2,2,2,2,2
%N a(n) is the least k > 0 such that k * n contains a digit 1 in its decimal representation.
%F 1 <= a(n) <= 5.
%F a(n) <= A190302(n).
%F a(n) = A317175(n, 1).
%F a(10 * n) = a(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) = 12/3 = 4.
%o (PARI) a(n) = for (k=1, oo, if (setsearch(Set(digits(k*n)), 1), return (k)))
%Y Cf. A011531, A190302, A317175.
%K nonn,base,easy
%O 1,2
%A _Rémy Sigrist_, Jul 23 2018