f(3mn + m + n) = 4f(m)f(n) + f(m) + f(n)
Source: IMO Shortlist 1996, N5
August 9, 2008
functionnumber theoryFunctional EquationsIMO Shortlist
Problem Statement
Show that there exists a bijective function such that for all :
f(3mn \plus{} m \plus{} n) \equal{} 4f(m)f(n) \plus{} f(m) \plus{} f(n).