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Putnam
2015 Putnam
B4
B4
Part of
2015 Putnam
Problems
(1)
Putnam 2015 B4
Source:
12/6/2015
Let
T
T
T
be the set of all triples
(
a
,
b
,
c
)
(a,b,c)
(
a
,
b
,
c
)
of positive integers for which there exist triangles with side lengths
a
,
b
,
c
.
a,b,c.
a
,
b
,
c
.
Express
∑
(
a
,
b
,
c
)
∈
T
2
a
3
b
5
c
\sum_{(a,b,c)\in T}\frac{2^a}{3^b5^c}
(
a
,
b
,
c
)
∈
T
∑
3
b
5
c
2
a
as a rational number in lowest terms.
Putnam
Putnam 2015
algebra
Summation
geometric series
RIP kent