Problem 133

ayan_2587 · Post by **ayan_2587** » Fri Oct 16, 2009 2:53 pm

Hello frnds....
need a bit of help here..
for the problem no: 133, I am unable to understand for what of value of n should the program be executed.
is there any upper limit of n...i mean what values of n should i try for??

stijn263 · Post by **stijn263** » Fri Oct 16, 2009 3:08 pm

Problem 133 (View Problem)

There's no upperlimit on n. (but perhaps you don't need to check for n all the way up to infinity?) Good luck!

Smaug · Post by **Smaug** » Sat Oct 24, 2009 7:14 pm

I have a quibble with the wording of this problem - given that 2 is prime, and a repunit must be odd, 2 is a prime which will never be a factor of a repunit. Surely it should be stated that odd primes are being searched for?

elendiastarman · Post by **elendiastarman** » Sat Oct 24, 2009 7:31 pm

Well....wouldn't 2 be one of the primes you're trying to find?

daniel.is.fischer · Post by **daniel.is.fischer** » Sat Oct 24, 2009 8:29 pm

Quite.

Smaug · Post by **Smaug** » Mon Oct 26, 2009 3:20 pm

elendiastarman wrote:Well....wouldn't 2 be one of the primes you're trying to find?

But in the example, it says that ''it is remarkable that 11, 17, 41, and 73 are the only four primes below one-hundred that can ever be a factor of R(10^n)" - and 2 is not included!

daniel.is.fischer · Post by **daniel.is.fischer** » Mon Oct 26, 2009 5:29 pm

Smaug wrote:
elendiastarman wrote:Well....wouldn't 2 be one of the primes you're trying to find?
But in the example, it says that ''it is remarkable that 11, 17, 41, and 73 are the only four primes below one-hundred that can ever be a factor of R(10^n)" - and 2 is not included!

''it is remarkable that 11, 17, 41, and 73 are the only four primes below one-hundred that can ever be a factor of R(10ⁿ)"
Probably you misread that as never.
Since we don't want to lay artificial traps, I'll think about wording it differently to avoid that particular error.

Smaug · Post by **Smaug** » Tue Oct 27, 2009 5:39 pm

Oops... I feel a bit silly now.

Thanks for the advice!

mynameisalreadytaken · Sun Oct 30, 2011 11:42 pm

Can anyone confirm the sum 20308 for all the primes below 5000?

Edit: Alright, never mind. Next time, i should take a closer look at the description: I actually summed up all the primes, that can be factors of R(10^n) -___-

leijurv · Post by **leijurv** » Fri Mar 01, 2013 1:17 am

Can anyone confirm 5701941 for the primes up to 10,000?

(And yes, 20308 is correct for the ones that will be a factor up to 5000)

thundre · Post by **thundre** » Fri Mar 01, 2013 6:37 pm

leijurv wrote:Can anyone confirm 5701941 for the primes up to 10,000?

My sum for that is 5701946.

Did you forget 5?

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Problem 133

Problem 133

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Quibble with Problem 133

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Re: Problem 133

Re: Problem 133

Re: Problem 133

Re: Problem 133

Lower limit

Re: Lower limit