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Almost the harmonic series

Source: 2018 AMC 12A #19

February 8, 2018
AMC

Problem Statement

Let AA be the set of positive integers that have no prime factors other than 22, 33, or 55. The infinite sum 11+12+13+14+15+16+18+19+110+112+115+116+118+120+\frac{1}{1} + \frac{1}{2} + \frac{1}{3} + \frac{1}{4} + \frac{1}{5} + \frac{1}{6} + \frac{1}{8} + \frac{1}{9} + \frac{1}{10} + \frac{1}{12} + \frac{1}{15} + \frac{1}{16} + \frac{1}{18} + \frac{1}{20} + \cdots of the reciprocals of the elements of AA can be expressed as mn\frac{m}{n}, where mm and nn are relatively prime positive integers. What is m+nm+n?
<spanclass=latexbold>(A)</span> 16<spanclass=latexbold>(B)</span> 17<spanclass=latexbold>(C)</span> 19<spanclass=latexbold>(D)</span> 23<spanclass=latexbold>(E)</span> 36<span class='latex-bold'>(A)</span> \text{ 16} \qquad <span class='latex-bold'>(B)</span> \text{ 17} \qquad <span class='latex-bold'>(C)</span> \text{ 19} \qquad <span class='latex-bold'>(D)</span> \text{ 23} \qquad <span class='latex-bold'>(E)</span> \text{ 36}