On Sun, 9 Nov 2003, eharsh82 wrote:

> Has anyone looked at these. This is how I define them :

>

> A Sierpinski number is an odd number k such that k.2^n +1 is not

> prime for any n > 0.

>

> A prime Sierpinski number is a prime number k such that k.2^n +1 is

> not prime for any n > 0.

>

> I have been trying to eliminate most primes k's under 271129, the

> smallest prime Sierpinski Number, by finding primes.

>

> Let me know if some one has already done this work or if you would

> like to help me find primes for k's under 271129.

>

How do you prove for a particular value of k that k*2^n+1 is never prime

for n > 0?

I can think of a few values of k, for example if k = a^n where n is

an odd power greater than 1 and a*2+1 is not prime then a^n*x^n+1 =

(a*x)^n + 1 is not prime for all x > 0. But how do you do it in general?

--Edwin