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Problems
Contests
National and Regional Contests
PEN Problems
PEN A Problems
101
101
Part of
PEN A Problems
Problems
(1)
A 101
Source:
5/25/2007
Find all composite numbers
n
n
n
having the property that each proper divisor
d
d
d
of
n
n
n
has
n
−
20
≤
d
≤
n
−
12
n-20 \le d \le n-12
n
−
20
≤
d
≤
n
−
12
.
Divisibility Theory