new post draft

Author: amitsaha

content/trailing-zeros-factorial-python.rst

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+Number of trailing zeros in the factorial of an integer
+=======================================================
+
+:date: 2020-01-02 19:50
+:category: tips
+:slug: trailing-zeros-factorial
+:summary: Use Python to find the number of trailing zeros in the factorial of an integer
+
+
+Hi all, I recently learned about a cool formula to calculate the number of
+trailing zeros in the factorial of a number. It has been a while since I 
+wrote a program to do something like this. So, I decided to change that and
+write this blog post. In the spirit of wring various "calculators", we will
+write a "number of trailing zero" calculator. First up though, let's refresh 
+some key relevant concepts.
+
+**Factorial**: The factorial of a number, ``n`` denoted by ``n!`` is the product ``n*(n-1)*(n-2)...*1``.
+For example, ``5! = 5*4*3*2*1 = 120``.
+
+**Trailing zeros**: The trailing zeros of a number is the number of zeros at the end of a number. For example,
+the number 567100 has **two** trailing zeros.
+
+**Floor**: The floor of a number is the greatest integer less than or equal to x. That is floor of 3.2 is 3
+and that of 3.5 is 3 and the floor of 3 is 3 as well.
+
+
+Now, coming back to the focus of this post, this document at brilliant.org wiki 
+explains the process in `detail <https://brilliant.org/wiki/trailing-number-of-zeros/>`__.
+
+The key bit there in is this formula:
+
+.. math::
+
+   \sum_{i=0}^{k}\floor*{\frac{n}{5^i}}
+
+where, ``n`` is the number for whose factorial we want to find the number of trailing zeros in and ``k`` 
+
+