On 2011-08-08, Deep <firstname.lastname@example.org> wrote: > I would appreciate it very much if someone can refer me to an > appropriate reference where following statement is justified. > > Statement: Every integer N that is not 2mod4 can be expressed as the > difference of two squares.
No reference necessary.
For odd numbers: 2n+1 = (n+1)^2 - n^2. For numbers divisible by 4: 4n = (n+1)^2 - (n-1)^2.
They may also have other representations, but these suffice to justify the statement.