Let n be a positive integer, can (2n + 1) & sup2; - 1 be divisible by 8? Why?

Let n be a positive integer, can (2n + 1) & sup2; - 1 be divisible by 8? Why?

(2n+1)²-1
=(2n+1+1)(2n+1-1)
=(2n+2)(2n)
=4n(n+1)
Either n or N + 1 must be even
So n (n + 1) is a multiple of 2
So 4N (n + 1) is a multiple of 8
So it's divisible by eight