- View SourceGroup,

I believe that if 'N' passes the 2-PRP test that either 3, 5, or 7 divides 'N-1', one or

all of them, or 'N' will be divisible by 3, 5, or 7 and be composite. I could only go

so far with my outdated computer and UBasic. Can anyone find a counter-example ???

Bill - View SourceIf you used your elderly computer to search for known results rather

than for computations you would have discovered

http://www.research.att.com/~njas/sequences/A055550 and, in particular,

the entry 264239

264239 = 139 * 1901

264238 = 2 * 13 * 10163

Paul

On Mon, 2010-02-01 at 06:18 -0800, Bill Bouris wrote:

>

> Group,

> I believe that if 'N' passes the 2-PRP test that either 3, 5, or 7

> divides 'N-1', one or

> all of them, or 'N' will be divisible by 3, 5, or 7 and be composite.

> I could only go

> so far with my outdated computer and UBasic. Can anyone find a

> counter-example ???

> Bill

>

>

>

>

>