N is a positive integer such that each of 3*N + 1 and 4*N + 1 is a perfect square.

Is N always divisible by 56?

If so, prove it. Otherwise, give a counterexample.

(In reply to Now, four values by Brian Smith)

56*1423694415=79,726,887,240, not 79,762,887,240, but that corrected number does work.

Posted by Charlie on 2010-04-01 23:07:13