olymmath

JBMO-SL 2016 C1

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Let SnS_{n} be the sum of reciprocal values of non-zero digits of all positive integers up to (and including) nn. For instance, S13=11+12+13+14+15+16+17+18+19+11+11+11+11+12+11+13S_{13}=\frac{1}{1}+\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+\frac{1}{5}+\frac{1}{6}+\frac{1}{7}+\frac{1}{8}+\frac{1}{9}+\frac{1}{1}+\frac{1}{1}+\frac{1}{1}+\frac{1}{1}+\frac{1}{2}+\frac{1}{1}+\frac{1}{3}. Find the least positive integer kk making the number k!⋅S2016k!\cdot S_{2016} an integer.

Dataset text NuminaMath olympiads. Quoted with source.

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