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# Exhaustion

*This problem was taken from the Hungarian magazine KoMaL. There are many other challenging problems in English on the KoMal website.*
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Age 16 to 18

Challenge Level

Find the positive integer solutions of the equation

\[ \left(1 + \frac{1}{a}\right)\left(1 + \frac{1}{b}\right) \left(1+ \frac{1}{c}\right) = 2. \]

The familiar Pythagorean 3-4-5 triple gives one solution to (x-1)^n + x^n = (x+1)^n so what about other solutions for x an integer and n= 2, 3, 4 or 5?

Find all 3 digit numbers such that by adding the first digit, the square of the second and the cube of the third you get the original number, for example 1 + 3^2 + 5^3 = 135.