Problem 615

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beco
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Problem 615

Post by beco » Mon Dec 04, 2017 10:03 pm

Congratulations to the first 100!

I've tried, but due to lots of not so much prime factors, I couldn't!

I'm specially amused by the time achieved by the Japanese flag user uwi. Just 10 minutes!

That got me thinking...

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Jochen_P
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Location: Stuttgart, Germany

Re: Problem 615

Post by Jochen_P » Thu Sep 20, 2018 8:43 am

Can someone confirm the 1000th number with at least 5 Prime Factors to be 9576 ?
thank you :)
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hk
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Re: Problem 615

Post by hk » Thu Sep 20, 2018 12:03 pm

This simple program tells you the answer:

Code: Select all

def primefactorcnt(n):
    res=0
    f=2
    while n>1:
        while n%f==0:
            n/=f
            res+=1
        f+=1
    return res
cnt=0
for n in xrange(2,10000):
    k=primefactorcnt(n)
    if k>=5:
        cnt+=1
        if cnt==1000:
            print n
            break
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Jochen_P
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Location: Stuttgart, Germany

Re: Problem 615

Post by Jochen_P » Mon Oct 01, 2018 5:19 pm

well, yeah, sure. Thanks :oops:
should've seen the ease of selftesting.

Now to find out where and why the easy to spot pattern from the example values breaks :(
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