回复：Maybe I am wrong. An Counterexample.

来源: 于 2012-03-11 13:04:23 [旧帖] [给我悄悄话] 本文已被阅读：次

Thanks.

But why 3y^2+286 is not square number?

suppose 3y^2+13, 13 has no factor of 3 and is not a square nubmer. But let y=1, it is 16=4*4.