Moved 20 to 26 to Python.

python/e023.py

@@ -1,40 +1,28 @@
-import math
-
-
-def get_proper_divisors(n):
-    proper_divisors = set([1])
-    for i in range(2, int(math.sqrt(n)) + 1):
-        if n % i == 0:
-            proper_divisors.add(i)
-            proper_divisors.add(n / i)
-    return proper_divisors
+from lib_misc import sum_proper_divisors
 
 
 def is_abundant(n):
-    return sum(get_proper_divisors(n)) > n
+    return sum_proper_divisors(n) > n
 
 
-def get_abundant_numbers_smaller(n):
-    ret = []
-    for i in range(1, n):
-        if is_abundant(i):
-            ret.append(i)
-    return ret
-
-
-def is_sum_of_two_abundant(n, abundant_numbers):
-    abundant_numbers_set = set(abundant_numbers)
-    for a1 in abundant_numbers:
-        if a1 > n:
+def is_sum_of_two_abundant(n, abundant_numbers, abundant_numbers_set):
+    for a in abundant_numbers:
+        if a > n:
             return False
-        elif (n - a1) in abundant_numbers_set:
+        d = n - a
+        if d in abundant_numbers_set:
             return True
-            
-    
+    return False
+
+
+def euler_023():
+    abundant_numbers = [n for n in range(1, 28123 + 1) if is_abundant(n)]
+    abundant_numbers_set = set(abundant_numbers)
+    return sum([n for n in range(1, 28123 + 1)
+                if not is_sum_of_two_abundant(n, abundant_numbers,
+                                              abundant_numbers_set)])
+
+
 if __name__ == "__main__":
-    abundant_numbers = get_abundant_numbers_smaller(30000)
-    cannot_be_written_as_sum_of_abundant = []
-    for i in range(28129):
-        if not is_sum_of_two_abundant(i, abundant_numbers):
-            cannot_be_written_as_sum_of_abundant.append(i)
-    print(sum(cannot_be_written_as_sum_of_abundant))
+    print("e023.py: {}".format(euler_023()))
+    assert(euler_023() == 4179871)