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?
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return n*(n+1)/2
def fac(n):
i=2
j=1
while i<= n/2:
if n%i==0:
j=j+1
i=i+1
return j+1
def fact(n):
if n%2==0:
return fac(n/2)*fac(n+1)
else:
return fac(n)*fac((n+1)/2)
i=1
while fact(i)<500:
i=i+1
print i, trg(i), fact(i)
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