Is the square of any odd number minus 1 a multiple of 8,

Is the square of any odd number minus 1 a multiple of 8,

(2n+1)^2-1=4n^2+4n=4n(n+1)
N and N + 1 are adjacent natural numbers, and one of them must be even
SO 2 divides n (n + 1) so 8 divides 4N (n + 1)