Pi_decimals.py

# Decimal's of Pi using Bailey-Borwein-Plouffe formula
# Juhani Kaukoranta, @jukaukor , on Pi's day 2018-03-14

from decimal import *
def pii(precision):
    getcontext().prec=precision
    s = Decimal(0)
    for k in range(0,precision):
        s = s + 1/Decimal(16)**k*(
        Decimal(4)/(8*k+1) -
        Decimal(2)/(8*k+4) -
        Decimal(1)/(8*k+5) -
        Decimal(1)/(8*k+6))
    return s

pidecimals = int(input("How many digits you want for Pi's value? "))
Pi_value = pii(pidecimals+1)
print ("Value of Pi with ",pidecimals," digit precision: ")
print(Pi_value)