RamanujanPi.py

# Modified Ramanujan's formula of sqrt(2)/pi
# Ramanujan wrote in 1914 his original formula of 1/pi
# Juhani Kaukoranta 18.6.2018

from decimal import *
import math


def RamanujanInversePi(precision):
    getcontext().prec=precision
    inverse = Decimal(0)
    for n in range(0,precision):
        inverse = inverse + Decimal(1)*math.factorial(4*n)/(math.factorial(n))**4*(26390*n+1103)/396**(4*n)

    inverse = inverse*4/9801
    return(inverse)

numbers = int(input("Kuinka monta numeroa haluat "))
inversePi = RamanujanInversePi(numbers)
print("sqrt(2)/pi = ",inversePi)