Moved 20 to 26 to Python.

python/e020.py

@@ -1,7 +1,11 @@
+from lib_misc import factorial
+
+
 def euler_020():
-    return 0
+    f_100 = factorial(100)
+    return sum(map(int, str(f_100)))
 
 
 if __name__ == "__main__":
-    assert(euler_020() == 1074)
+    assert(euler_020() == 648)
     print("e020.py: {}".format(euler_020()))