On Nonsquare Powerful Numbers
R. A. Mollin, Peter Walsh · The Fibonacci Quarterly · 1987
As introduced by Golomb in [l]s a powerful number n is a positive integer which has no prime appearing to the first power in its canonical prime decomposition; i.e., if a prime p divides n, then p 2 divides n. If n and m are powerful numbers, then n- m is said to be a proper difference of powerful numbers