*nonzero perfect square*of the form X

_{1}X

_{1}X

_{2}X

_{2}, where X

_{1}and X

_{2}are base-N digits whether same or different.

Derive a general formula that expresses X

_{1}X

_{1}X

_{2}X

_{2}in terms of N, where N is an integer > 3.

*** X

_{1}X

_{1}X

_{2}X

_{2}is a concatenation of the digits and not the product.