def pe12(sub=500):
"""
What is the value of the first triangle number
to have over five hundred divisors?
>>> pe12()
76576500
"""
for t in triangle_numbers():
c = count_divisors(t)
if c >= sub:
return (t)
return -1
def pe12(sub=500):
"""
What is the value of the first triangle number
to have over five hundred divisors?
>>> pe12()
76576500
"""
for t in triangle_numbers():
c = count_divisors(t)
if c >= sub:
return t
return -1
def problem12():
"""
The sequence of triangle numbers is generated by adding the natural
numbers. So the 7th triangle number would be
1 + 2 + 3 + 4 + 5 + 6 + 7 = 28. The first ten terms would be:
1, 3, 6, 10, 15, 21, 28, 36, 45, 55, ...
Let us list the factors of the first seven triangle numbers:
1: 1
3: 1,3
6: 1,2,3,6
10: 1,2,5,10
15: 1,3,5,15
21: 1,3,7,21
28: 1,2,4,7,14,28
We can see that 28 is the first triangle number to have over five
divisors.
What is the value of the first triangle number to have over five hundred
divisors?
This is a brute force solution. You could cut out a lot of computation
by starting the triangle generator at a higher number than, well, 1. If
28 has just 5 divisors, a it's likely that a number with 500 divisors is
going to be relatively large.
But, in the interest of simplicity and assumption free code, we're going
to brute force this.
"""
divisors = 0
tri_generator = triangle_numbers()
while divisors < 500:
tri_number = next(tri_generator)
divisors = divisor_counter(tri_number)
print tri_number, divisors
return tri_number
from itertools import groupby
from utils import triangle_numbers, factorize
def number_of_factors(n):
prime_factors = factorize(n)
grouped_factors = [list(g) for k, g in groupby(prime_factors)]
count = 1
for factor_group in grouped_factors:
count *= len(factor_group) + 1
return count
for t in triangle_numbers():
n = number_of_factors(t)
if n > 500:
print(t)
break
