Eqn (10) from Greenhall2004

def greenhall_BasicSum(J, M, S, F, alpha, d):
    """ Eqn (10) from Greenhall2004 """
    first = pow(greenhall_sz(0, F, alpha, d), 2)
    second = (1-float(J)/float(M))*pow(greenhall_sz(float(J)/float(S), F, alpha, d), 2)
    third = 0
    for j in range(1, int(J)):
        third += 2*(1.0-float(j)/float(M))*pow(greenhall_sz(float(j)/float(S), F, alpha, d), 2)
    return first+second+third