can anyone help me make this code faster

class Permutation {

static int answer = 0;
static void combinationUtil(int arr[], int n, int r, int index,
                            int data[], int i,int d)
{
    if (index == r)
    {
        float k =0;
        for (int j=0; j<r; j++)
        {
            k += 1/(Math.pow(data[j],2));
        }
        if((float)1/d == k)
            answer++;
    return;
    }

    if (i >= n)
    return;

    data[index] = arr[i];
    combinationUtil(arr, n, r, index+1, data, i+1,d);


    combinationUtil(arr, n, r, index, data, i+1,d);
}

static void printCombination(int arr[], int n,int d)
{
    int r=0;
    while(r <= n)
    {
        int data[]=new int[r];
        combinationUtil(arr, n, r, 0, data, 0,d);
        r++;
    }
}

public static void main (String[] args) {
    Scanner s = new Scanner(System.in);
    int d = s.nextInt();
    int n = s.nextInt();
    int arr[] = new int[n-1];
    for(int i = 2;i <= n;i++)
    {
        arr[i-2] = i;
    }
    printCombination(arr, n-1,d);
    System.out.println(answer);
}

}