int[][][] list = new int[3][2][1];
for (int i = 0; i<list.length; i++){
    for (int j = 0; j<list[i].length; j++){
        int sum = 0;
        for (int k = 0; k<list[i][j].length; k++){
            sum += k;
        }
        list[i][j][0] = sum;
    }
}