Solution to Problem 28

Author: daniel-s-ingram

Project Euler/Problem 28/sol1.py

@@ -1,11 +1,12 @@
 from __future__ import print_function
+from math import ceil
 
 def diagonal_sum(n):
 	total = 1
 
-	for i in xrange(n/2):
-		odd = 2*(i+1)+1
-		even = 2*(i+1)
+	for i in xrange(1, int(ceil(n/2.0))):
+		odd = 2*i+1
+		even = 2*i
 		total = total + 4*odd**2 - 6*even
 
 	return total