MathDB
Problems
Contests
National and Regional Contests
PEN Problems
PEN D Problems
14
14
Part of
PEN D Problems
Problems
(1)
D 14
Source:
5/25/2007
Determine the number of integers
n
≥
2
n \ge 2
n
≥
2
for which the congruence
x
25
≡
x
(
m
o
d
n
)
x^{25}\equiv x \; \pmod{n}
x
25
≡
x
(
mod
n
)
is true for all integers
x
x
x
.
modular arithmetic
Congruences