Question

If k(N) denotes the number of ways of expressing N
as a difference of two perfect squares, then which of
the following is the least?
(A) k(187) (B) k(120) (C) k(110) (D) k(105)​

Answer 1

Answer:

The number of ways (K(N)),

a natural number (N) can be expressed as the sum of squares of natural numbers, should always be,

K(N) >= [N / 2] - 1.