What is three prime number?

Posted by

Nikola 2 May 2008 18:18

Can anyone help me please? I don't understand what is three prime number? :S

Re: What is three prime number?

My english is not good...

Let my try to explane you on example:

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

1274 - not

this is not three prime number because

127 - this is 3.-digit prime nubmer , but

274 - this is not 3.-digit prime number...

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

1137 - is

this is three prime number because

113 - this is 3.-digit prime number, and

137 - this is 3.-digit prime number

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

So every 3 consecutive digits in number X must be 3.-digit prime number...

I hope this help...

Re: What is three prime number?

It's not true number is three digits prime number if any three digits are prime

Re: What is three prime number?

"Pasha calls an integer a threeprime number if any three consecutive digits of this integer form a three-digit prime number."

So if we write number A as A[1]A[2]...A[n] (A[i] - i-th digit of this number), than whole number A will be 'threeprime' if and only if for each i=1,2..., n-2 number A[i]A[i+1]A[i+2] is prime number.

Re: What is three prime number?

Posted by

Nikola 4 May 2008 06:11

I understand now. Thanks a lot guys. The problem won't be problem anymore :)

Edit: Except one more thing? 3 digit number is threeprime only if the number is prime right?

Example: 101 is prime number so that means it's also a threeprime number right? Or that's not always right?

*Edited by author 04.05.2008 06:39*

*Edited by author 04.05.2008 06:47*

Re: What is three prime number?

Posted by

iOli 20 Dec 2017 20:54

Thank you very much :)