On 23.04.2018 17:59, Steve Holden wrote:

While Tim's expression might look (superficially) like C, the five-line alternative isn't exactly an inspiring example of Pythonicity, is it?

What about

diff = x - x_base
if diff and gcd(diff, n) > 1:
    return gcd(diff, n)

# or

if (x - x_base) and gcd(x - x_base, n) > 1:
    return gcd(x - x_base, n)

and have the interpreter handle the optimization, or apply an lru_cache? ;-)

Cheers,
Sven