2nd Iberoamerican 1987

Define the sequence p₁, p₂, p₃, ... as follows. p₁ = 2, and p_n is the largest prime divisor of p₁p₂ ... p_n-1 + 1. Prove that 5 does not occur in the sequence.

Solution

See Australian 82/5

2nd Ibero 1987

© John Scholes
jscholes@kalva.demon.co.uk
1 July 2002
Last corrected/updated 8 Feb 04