All about flooble | fun stuff | Get a free chatterbox | Free JavaScript | Avatars
 perplexus dot info

 A Composite Determination Problem (Posted on 2006-04-23)
Determine whether or not N is a composite number, where

N = 675*2621 + 677*2610 - 1

NOTE:
A prime number (or a prime) is a natural number that has exactly two (distinct) natural number divisors, which are 1 and the prime number itself. A composite number is a positive integer which has a positive divisor other than one or itself. By definition, every integer greater than one is either a prime number or a composite number. The numbers 0 and 1 are considered to be neither prime nor composite.

 See The Solution Submitted by K Sengupta Rating: 4.3333 (3 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
 Solution | Comment 10 of 14 |
N = (26^2 - 1)26^21 + (26^2 + 1)26^10 - 1 =
26^23 - 26^21 + 26^12 + 26^10 - 1 =
(26^11 - 26^10 + 1)(26^12 + 26^11 - 1),
which is is composite as both sides are clearly greater than 1.
 Posted by Nick Hobson on 2006-04-23 18:29:27

 Search: Search body:
Forums (0)