Skipping the terms of a sequence
Source: IMO LongList 1988, West Germany 3, Problem 16 of ILL
October 22, 2005
algebra unsolvedalgebra
Problem Statement
If runs through all the positive integers, then f(n) \equal{} \left[n \plus{} \sqrt {\frac {n}{3}} \plus{} \frac {1}{2} \right] runs through all positive integers skipping the terms of the sequence a_n \equal{} 3 \cdot n^2 \minus{} 2 \cdot n.