IMO Shortlist 1993 problem N1
Dodao/la:
arhiva2. travnja 2012. A natural number
is said to have the property
if, for all
divides
whenever
divides
a.) Show that every prime number
has property
b.) Show that there are infinitely many composite numbers
that possess property
%V0
A natural number $n$ is said to have the property $P,$ if, for all $a, n^2$ divides $a^n - 1$ whenever $n$ divides $a^n - 1.$
a.) Show that every prime number $n$ has property $P.$
b.) Show that there are infinitely many composite numbers $n$ that possess property $P.$
Izvor: Međunarodna matematička olimpijada, shortlist 1993