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2.1
2.1
Part of
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(1)
0421 number theory 4th edition Round 2 p1
Source:
5/7/2021
For a positive integer
n
n
n
let
σ
(
n
)
\sigma (n)
σ
(
n
)
be the sum of all its positive divisors. Find all positive integers
n
n
n
such that the number
σ
(
n
)
n
+
1
\frac{\sigma (n)}{n + 1}
n
+
1
σ
(
n
)
is an integer.
number theory
4th edition