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Problems
Contests
National and Regional Contests
PEN Problems
PEN A Problems
10
10
Part of
PEN A Problems
Problems
(1)
A 10
Source:
5/25/2007
Let
n
n
n
be a positive integer with
n
≥
3
n \ge 3
n
≥
3
. Show that
n
n
n
n
−
n
n
n
n^{n^{n^{n}}}-n^{n^{n}}
n
n
n
n
−
n
n
n
is divisible by
1989
1989
1989
.
Euler
number theory
Divisibility Theory