Problem 248

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LarryBlake
Posts: 100
Joined: Sat Aug 29, 2009 8:49 pm

Problem 248

Post by LarryBlake »

Problem 248 (View Problem)
I've generated about half a million numbers with this Totient value, but apparently my 150,000th is not the one desired. Could someone post the 100th and the 1000th, so I can check my results? If you prefer, I'll PM them to you. Thanks.
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wrongrook
Posts: 745
Joined: Sat Oct 17, 2009 10:39 pm

Re: Problem 248

Post by wrongrook »

I make these:
100th is 6239393627
1000th is 6359386477
Good luck!

This probably sounds incredibly patronising, so please understand that no offence is intended, but I suspect you will find it helpful to write a simple bruteforce algorithm to check the results for small numbers :)
Last edited by wrongrook on Sun Jan 24, 2010 10:22 pm, edited 1 time in total.
LarryBlake
Posts: 100
Joined: Sat Aug 29, 2009 8:49 pm

Re: Problem 248

Post by LarryBlake »

Thanks. As I suspected, I seem to be missing a few.

Is 6227267713 the 10th?

BTW, wrongrook, I'm truly amazed by your progress. For a while, we had a similar number of answers, but you've left me in the dust. Great job. :)
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wrongrook
Posts: 745
Joined: Sat Oct 17, 2009 10:39 pm

Re: Problem 248

Post by wrongrook »

I agree with your value for 10.

By the way I hope you didn't read the reply too early as I had off by 1 errors in them the first time!

I've been really enjoying this site and probably spending far too much time on it.
I've been amazed by how much interesting and understandable mathematics I was able to discover through solving these problems. (I had no doubt that there was loads of interesting maths around, the surprising part is that through this site I have been able to come to grips with some of it at last.)

I have had a bit of an unfair advantage though in that I had just resigned my job when I discovered this site and my employer insisted on me working out my 3 month notice period just in case something turned up for me to do...
cataluna0213
Posts: 1
Joined: Tue May 18, 2010 4:50 pm

Re: Problem 248

Post by cataluna0213 »

I'm confused as to what the question is asking.

First of all, it would have been nice if the problem defined totient function.

What I'm stuck at is 'find the 150,000th such number. What is 'such number?'' An n such that the totient is also 13! or a totient that is any factorial?
harryh
Posts: 2091
Joined: Tue Aug 22, 2006 9:33 pm
Location: Thessaloniki, Greece

Re: Problem 248

Post by harryh »

The 150,000th number n for which φ(n) = 13!
maaartinus
Posts: 3
Joined: Sat May 23, 2015 12:09 pm

Re: Problem 248

Post by maaartinus »

I wonder what I'm doing wrong as I get only 148394 numbers. I get all the above values (the 10th, 100th and 1000th number) right.
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