--- In

primenumbers@yahoogroups.com, "Jens Kruse Andersen"

<jens.k.a@...> wrote:

>

> I wrote:

> > A Proth prime is k*2^n+1 with k < 2^n.

> > A PrimoProth prime is based on this, a Proth prime where k is a

primorial:

> > m#*2^n+1 with m# < 2^n

> > However, m#*2^n-1 with m# < 2^n also appears to be allowed.

>

> After looking at more Google hits, it actually appears that the few

people

> searching or listing PrimoProths use different definitions or don't

state a

> definition at all. This confusion may be caused by Henri Lifchitz who

> introduced the concept but himself seems unclear with the definiton and

> inconsistent in the alleged records, both regarding whether there is an

> upper and a lower limit on m#.

>

> --

> Jens Kruse Andersens

>

I was involved some years ago as a coordinator for primes of the

series n#/2*2^n+/1, which I called primoproths, influenced by Henri

-see

http://home.btclick.com/rwsmith/pp/page1.htm
As suspected the largest primes discovered involve k=3 and k=15. The

Riesel series k=15 is being actively searched and is at n=1834000 see:

http://www.mersenneforum.org/showthread.php?t=6338. k=3 search is well

known.

The attractions of primoproths were diminished when it was discovered

that Payam numbers gave greater density of primes and active searching

went into abeyance.

But these are good finds, so congrats