Can someone help me pls??

Can someone explane me why you get as result of this process: true, true, false, true?

Code:

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public class PaliMod {
        private int delta;
        public PaliMod(int mnD) {
                delta = mnD;
        }
        private boolean check(int [] rij,int d) {
                if (d >= rij.length - d - 1) return true;
                if ((rij[d]- rij[rij.length-d-1]) % delta == 0)
                                return check(rij,d+1);
                return false;
        }
        public boolean check(int [] eenRij) {
                return check(eenRij,0);
        }
        public static void main(String[] args) {
                int [] rij1 = {1,67,13,2,14};
                int [] rij2 = {1};
                int [] rij3 = {1,130};
                PaliMod gen = new PaliMod(13);
                System.out.println(gen.check(rij1));
                System.out.println(gen.check(rij2));
                System.out.println(gen.check(rij3));
                System.out.println(new PaliMod(111).
check(new int[]{1,2,3,4,448,336,224,112}));
        }
}

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Code:

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--------------------Configuration: <Default>--------------------
true
true
false
true

Process completed.

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just check the flow. starting from main() ..