- #1
yeland404
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Homework Statement
let n be an integer . Prove the congruence below.
n^21 [itex]\equiv[/itex] n mod 30
Homework Equations
n^7 [itex]\equiv[/itex] n mod 42
n^13 [itex]\equiv[/itex] n mod 2730
The Attempt at a Solution
to prove 30| n^21-n,it suffices to show 2|n^21-n,3|n^21-n,5|n^21-n
and how to prove them?