Library / /81 of 99

, 2025

Number theory Difficulty 3.0 AMC 10/12 Prove it United Kingdom

The sequence $k_n$ is defined by $k_1 = 19$ , $k_2 = 11$ and $k_{n+2} = k_n + k_{n+1}$ for $n \ge 1$ . How many of the first 2025 terms in the sequence are even?

Want a route through all this instead of an archive? The track puts 2,604 problems in a working order, from Junior Challenge level to the IMO shortlist.

Source: UK Mathematics Trust, licensed © UK Mathematics Trust; past papers published free at ukmt.org.uk. Statement reproduced verbatim; metadata (topic, difficulty) added by this project. Solutions are the publisher's, linked not copied.