MathDB

Gunga P19

Source:

October 16, 2021

MOAA 2021Gunga

Problem Statement

Let

S

be the set of triples

(a,b,c)

of non-negative integers with

a+b+c

even. The value of the sum

\sum_{(a,b,c)\in S}\frac{1}{2^a3^b5^c}

can be expressed as

\frac{m}{n}

for relative prime positive integers

m

and

n

. Compute

m+n

.
Proposed by Nathan Xiong

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