-
Notifications
You must be signed in to change notification settings - Fork 0
/
pro23.py
30 lines (25 loc) · 798 Bytes
/
pro23.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
LIMIT = 28124
def non_abundant_sums():
"""
find the sum of all the positive integers
which cannot be written as the sum of two abundant numbers.
:return:
"""
# the sum of divisors of every number
divisor_sum = [0] * LIMIT
for i in range(1, LIMIT):
for j in range(i * 2, LIMIT, i):
divisor_sum[j] += i
# abundant numbers
abundant_nums = [i for (i, x) in enumerate(divisor_sum) if x > i]
expressible = [False] * LIMIT
for i in abundant_nums:
for j in abundant_nums:
if i + j < LIMIT:
expressible[i + j] = True
else:
break
ans = sum(i for (i, x) in enumerate(expressible) if not x)
return str(ans)
if __name__ == "__main__":
print(non_abundant_sums())