blob: 9e11164357bfd8022550b61e44b8d1ca1b08e669 (
plain)
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
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
|
#!/usr/bin/env python3
# Challenge 008
#
# Challenge #1
# Write a script that computes the first five perfect numbers. A perfect number
# is an integer that is the sum of its positive proper divisors (all divisors
# except itself). Please check Wiki for more information. This challenge was
# proposed by Laurent Rosenfeld.
import sys
def is_prime(n):
if n <= 1:
return 0
elif n <= 3:
return 1
elif n % 2 == 0 or n % 3 == 0:
return 0
else:
for i in range(5, n+1, 6):
if i*i>n:
break
if n % i == 0 or n % (i+2) == 0:
return 0
return 1
def next_prime(n):
if n<=1:
return 2
n += 1
while not is_prime(n):
n += 1
return n
# Euclid proved that 2^(p-1)*(2^p - 1) is an even perfect number
# whenever 2p - 1 is prime
def perfect_iter():
p = 1
while True:
p = next_prime(p)
f = (2**p)-1
if is_prime(f):
yield (2**(p-1))*f
count = int(sys.argv[1])
for n in perfect_iter():
print(n)
count -= 1
if count<=0:
break
|
