MathDB
Turkey NMO 2010 1st Round - P04 (Combinatorics)

Source:

July 26, 2012
factorial

Problem Statement

How many positive integers less than 20102010 are there such that the sum of factorials of its digits is equal to itself?
<spanclass=latexbold>(A)</span> 5<spanclass=latexbold>(B)</span> 4<spanclass=latexbold>(C)</span> 3<spanclass=latexbold>(D)</span> 2<spanclass=latexbold>(E)</span> None <span class='latex-bold'>(A)</span>\ 5 \qquad<span class='latex-bold'>(B)</span>\ 4 \qquad<span class='latex-bold'>(C)</span>\ 3 \qquad<span class='latex-bold'>(D)</span>\ 2 \qquad<span class='latex-bold'>(E)</span>\ \text{None}