Adopted new convention from template

src/Python/Problems001-050/Problem015.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python3
+#!/usr/bin/env python
 """
 Created on 7 Jan 2018
 
@@ -10,22 +10,23 @@ https://projecteuler.net/problem=15
 """
 
 from math import factorial
+
 from utils import timeit
 
 
 @timeit("Problem 15")
 def compute():
     """
-    Starting in the top left corner of a 2×2 grid, and only being able to
+    Starting in the top left corner of a 2x2 grid, and only being able to
     move to the right and down, there are exactly 6 routes to the bottom
     right corner.
 
-    How many such routes are there through a 20×20 grid?
+    How many such routes are there through a 20x20 grid?
     """
+
     n = 20
-    return int(factorial(2*n) / (factorial(n) * factorial(2*n - n)))
+    return int(factorial(2 * n) / (factorial(n) * factorial(2 * n - n)))
 
 
 if __name__ == "__main__":
-
-    print(f"Result for Problem 15: {compute()}")
+    print(f"Result for Problem 15 is {compute()}")