MathDB

10

Part of 2009 Switzerland - Final Round

Problems(1)

4^n + 1 has a prime divisor > 20

Source: Switzerland - 2009 Swiss MO Final Round p10

12/26/2022
Let n>3n > 3 be a natural number. Prove that 4n+14^n + 1 has a prime divisor >20> 20.
number theorydivisor