Minimum value of sum over sequence elements
Source: IMO Shortlist 1997, Q 26
August 10, 2008
inequalitiesalgebraminimizationSequenceFibonacciIMO Shortlist
Problem Statement
For every integer determine the minimum value that the sum \sum^n_{i\equal{}0} a_i can take for nonnegative numbers satisfying the condition a_0 \equal{} 1, a_i \leq a_{i\plus{}1} \plus{} a_{i\plus{}2} for i \equal{} 0, \ldots, n \minus{} 2.