// Loop through world seeds
for (long worldSeed = 0; worldSeed != -1; worldSeed++) {
    // Create a random sequence object
    WitherSkeletonRandomSequence wsrs = new WitherSkeletonRandomSequence(worldSeed);
    // Check for 3 skulls in the first 3 kills with a looting 3 sword
    if (wsrs.has3SkullsOutOf(3, 3)) {
        // Print successful seed and return
        System.out.println(worldSeed);
        return;
    }
}