at most one of 2^{2^n}+ 1 and 6^{2^n}+ 1 is prime
Source: 12th or 13th QEDMO problem 6 (11. - 15. 12. 2013) https://artofproblemsolving.com/community/c2400093_2013_qedmo_13th_or_12th
July 5, 2021
number theoryprime
Problem Statement
A composite natural number is called happy if at most one of the numbers and is prime. Show that there are infinitely many happy numbers.