please i need help with this code it is giving me error

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package javaapplication6;

class Assignment5Recursion

{

public static int puzzleFormula(int n)

{

return 2*n*n + 2*n + 1;

}

public static int puzzleLoop(int n)

{

int sum = 2*n + 1;

for (int i = 1; i <= n; i++)

{

sum += 2*(2*i-1);

}

return sum;

}

public static int puzzleRecurse(int n)

{

if(n==0)

{

return 1;

}

else

{

return puzzleRecurse(n-1) + 4*n;

}

}

}