Pharmacode (Laetus) calculation script

pharmacode.py

#!/bin/env python
import sys

def pharmacode(v):
	r = ''
	while v:
		t = 1 - ( v % 2 )
		r = str(t) + r
		v = (v - t) / 2
	return r

if __name__ == '__main__':
	print(pharmacode(int(sys.argv[1])))

how to calculate the pharmacode value.