added my TikZ examples

tikz/birthday-paradox/calculate.py

@@ -0,0 +1,14 @@
+#!/usr/bin/python
+# -*- coding: utf-8 -*-
+
+from math import factorial
+from gmpy import bincoef
+
+f = open('data.csv', 'w')
+f.write('People\tprobability\n')
+
+def prob(people):
+    return 1.0 - float(factorial(people)*bincoef(365,people))/(365**people)
+
+for people in xrange(60+1):
+    f.write("%i\t%f\n" % (people, prob(people)))