perplexus.info :: Numbers : 10001, 100010001, ....

10001, 100010001, .... (Posted on 2003-05-23)

Consider the following sequence:

10001, 100010001, 1000100010001, 10001000100010001, 100010001000100010001,....

Show that none of them are prime numbers.

See The Solution Submitted by Fernando

Rating: 3.3333 (6 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)

re: First observations

Comment 12 of 12 |

(In reply to First observations by Brian Smith)

If the number of ones in a member of the sequence is A MULTIPLE OF 3, then the member itself is DIVISIBLE BY 3.

Posted by Ady TZIDON on 2013-02-27 06:54:12

Please log in:

Login:
Password:
Remember me:

Sign up! \| Forgot password

Search:

Search body:

Forums (0)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (12)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Chatterbox:


perplexus dot info