you had your brackets wrong for your denominator:
term = (double)(calculate(4*i)*(1103+(26390*i)))/((Math.pow(calculate(i), 4))*Math.pow(396, (4*i)));
Try using doubles for your calculations. And with a value of k = 30, the result is 3.141592653589793
And determining the value of PI is like applying stochastics to find a deterministic value, using large iterations gives a better precision