title:
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?
「三角数」即用递增的自然数相加得到的数，因此第7个三角数为1 + 2 + 3 + 4 + 5 + 6 + 7 = 28。前10个三角数为：
1, 3, 6, 10, 15, 21, 28, 36, 45, 55, ...
先让我们来看看前7个三角数各自都有哪些因数吧：
可见，28是第一个拥有超过5个因数的三角数。
那么第一个拥有超过500个因数的三角数是……？
import time def getCount(a): count=0 b=a if a==1: return 1 if a%2==0: i=2 else : i=3 while i < b: if a%i==0: count+=2 b=a/i if b==i: count-=1 break i+=1 return count+2 s=0 i=1 start=time.time() while True: s += i size=getCount(s) if size >= 500: break i+=1; stop=time.time() print "time is ",stop-start print s
projecteuler---->problem=12----Highly divisible triangular number,布布扣,bubuko.com
projecteuler---->problem=12----Highly divisible triangular number
原文：http://blog.csdn.net/q745401990/article/details/27810969