IMO 2017 Shortlist N1
The sequen e a0,a1,a2,... of positive integers satis es an1 “ ? an, if ? an is an integer an 3, otherwise for every n ě ...
Category: Number Theory
Problem
The sequen e a0,a1,a2,... of positive integers satis es
an1 “ #? an, if ? an is an integer an 3, otherwise
for every n ě 0.
Determine all values of a0 ą 1 for whi h there is at least one number a su h that an “ a for
in nitely many values of n.
(South Afri a)