Gaussian Integers

[sven-h.simon]

Meanwhile I got the article of Spira. I like his definition, because it depends 
on the unique factorization of imaginary numbers. From my feelings, the strength 
of an argument to consider only positive numbers as divisors of a numbers is 
less than normal, when one is dealing with imaginary numbers, where i**2 = -1.

Even Spira says, that there are many possibilities to define a Sigma for 
imaginary numbers.

I found another interesting article about 'Mersenne Primes In Imaginary 
Quadratic Number Fields' with Google. There are numbers (1+i)**n-1, which are 
Gaussian primes. n has to be prime. The sequence in OEIS is A057429, found by 
Mike Oakes and others. They use Spiras definition too.

Sven Simon
Germany