Problem 263

[MrDrake]

I'm sure the numbers I have are correct, but it says the answer is wrong. Here are the middle 3 digits of my four numbers:

***
***
***
***

Could someone verify them or otherwise?

EDIT: removed

[TripleM]

Check your 567.

[niino]

A pair of consecutive prime numbers with a difference of six is called a sexy pair.
You may miss the condition.

[MrDrake]

Yeah, I missed the condition with my 567. Only two lines to fix it luckily!

[genious999]

Why couldn't it be "Find the sum of the first three engineers’ paradises."
Either I'm doing something wrong, or the fourth is many orders of magnitude larger than the third

[Jochen_P]

It would really help to know what the first engineers' paradise number is

[hk]

Why couldn't it be "Find the sum of the first three engineers’ paradises."
Either I'm doing something wrong, or the fourth is many orders of magnitude larger than the third

If it helps you debugging: the fourth has 1 digit more than the third.

[genious999]

Why couldn't it be "Find the sum of the first three engineers’ paradises."
Either I'm doing something wrong, or the fourth is many orders of magnitude larger than the third

If it helps you debugging: the fourth has 1 digit more than the third.

Blah I found a bug. Thanks. I was beginning to get a bit worried when after running for about a day it had turned up nothing. Turns out I had made the loop increment in the wrong place, so for a day it had been running looping over the same incorrect range. Given your information that the fourth has one more digit than the third, it should have taken a max of 20 minutes. Oh well. Thanks again for the help

[mrtollefson]

Hi All -

Having difficulty with the definition of "practical" from the example for 6. In particular, the meaning for sum. If 1=1 and 2=2 are sums, why is 3=3 not a sum? Or maybe it is...

but for 4, why is 1 + 1 + 1 + 1 not a sum? Or, in other words, why is every number not practical?

Should I take the "sum of distinct divisors" to mean the "sum of any one or two distinct divisors"?

Proceeding that way, for now.

...mrt

[harryh]

why is 1 + 1 + 1 + 1 not a sum?

It's a sum, but it's not a sum of distinct divisors; it does not have to be a sum of only one or two divisors, but the divisors making up the sum must be distinct (i.e. different from each other).

[mrtollefson]

Thanks. I wasn't even thinking about more than 2. Liked it better my way

[mrtollefson]

OK. Time for more get-smart. The Wiki page on Practical Numbers

http://en.wikipedia.org/wiki/Practical_ ... al_numbers

(among others) gives 8 as a practical number. The distinct divisors are 1, 2, 8. Taking "distinct" to mean "use once," from the definition, how do we fill in for 4, 5, 6, 7?

...confused in Eulerville

[genious999]

OK. Time for more get-smart. The Wiki page on Practical Numbers

http://en.wikipedia.org/wiki/Practical_ ... al_numbers

(among others) gives 8 as a practical number. The distinct divisors are 1, 2, 8. Taking "distinct" to mean "use once," from the definition, how do we fill in for 4, 5, 6, 7?

...confused in Eulerville

4 is also a divisor of 8.
4+1=5
4+2=6
4+2+1=7

[mrtollefson]

This time I might have it:

Distinct divisors != 1, Prime Factors, n

Thanks.

...mrt

[mrtollefson]

Wandering around the PE263 desert. I'm up to 1.3*10^7 and no sign of any paradise. I'm beginning to doubt my "map."

Should I?

...mrt

[zwuupeape]

No

[sgotenks]

i thought about this problem for 2 weeks but nothing.......i'm a beginner with python....anyway
i have aquestions:

The problem says:A pair of CONSECUTIVE prime numbers with a difference of six is called a sexy pair (since "sex" is the Latin word for "six"). The first sexy pair is (23, 29).

At the beginning i missed this conditions cause in Wiki http://en.wikipedia.org/wiki/Sexy_prime doesn't tell about "CONSECUTIVE", so for me the first pair was 5-11 and not 23-29.
i fixed it but i'm not even able to find the first paradise. I checked till the first triple sexy pair after 2 millions, but nothing.
I'm quite sure that my algorithm doesn't miss any practical number or triple sexy pair (but maybe i'm wrong, if the first paradise is lower the 2 million), so maybe the problem is that is to slow cause to get 2millions it took like 5minutes......and mybe the first paradise is far away from 2 millions....Can you give me a hint pls????

[TripleM]

The first paradise is quite a long way after 2 million

[The_X]

Are there any paradises below 100 million? My code says there isn't, but please let there be.

[legavrik]

The title should be "An engineer's dream come true" not "An engineers' dream come true" as there is only one engineer