MathDB
Distinct prime factor set

Source: 2016 BAMO-8 #3, 2016 BAMO-12 #1

February 24, 2016
B8number theoryprime factorizationPrime factorfactor

Problem Statement

The <spanclass=latexitalic>distinctprimefactors</span>{<span class='latex-italic'>distinct prime factors</span>} of an integer are its prime factors listed without repetition. For example, the distinct prime factors of 4040 are 22 and 55.
Let A=2k2A=2^k - 2 and B=2kAB= 2^k \cdot A, where kk is an integer (k2k \ge 2). Show that, for every integer kk greater than or equal to 22,
[*] AA and BB have the same set of distinct prime factors. [*] A+1A+1 and B+1B+1 have the same set of distinct prime factors.