Posted: Thu Dec 02, 2004 4:48 pm    Post subject: Number theory( factorial )

Let

Find all such that is a square number.

Posted: Thu Dec 02, 2004 5:42 pm    Post subject:

For n>=5, A(n)=4!+3!+2!+1=3(mod 5) Since 3 is quadratic nonresidue, n