def bellard(n): pi=0 for i in range(n+1): pi+=(-2**5/(4*i+1)-1/(4*i+3)+2**8/(10*i+1)-2**6/(10*i+3)-2**2/(10*i+5)-2**2/(10*i+7)+1/(10*i+9)) *(-1)**i/(2**6*2**(10*i)) return pi