Let n 4. In this article, we will determine the asymptotic behavior of the size of the set of integral points (a 0 : · · · : a n ) on the hyperplane n i=0 X i = 0 in ސ n such that a i is squareful (an integer a is called squareful if the exponent of each prime divisor of a is at least two) and |a i | B for each i ∈ {0, . . . , n}, when B goes to infinity. For this, we will use the classical Hardy-Littlewood method. The result obtained supports a possible generalization of the Batyrev-Manin program to Fano orbifolds.