Determine maximum and minimum value of a(n) over n <= 1996
Source: IMO Shortlist 1996, A9
August 9, 2008
floor functionmodular arithmeticalgebraSequencerecurrence relationIMO Shortlist
Problem Statement
Let the sequence a(n), n \equal{} 1,2,3, \ldots be generated as follows with a(1) \equal{} 0, and for
a(n) \equal{} a\left( \left \lfloor \frac{n}{2} \right \rfloor \right) \plus{} (\minus{}1)^{\frac{n(n\plus{}1)}{2}}.
1.) Determine the maximum and minimum value of over and find all for which these extreme values are attained.
2.) How many terms are equal to 0?