Hi Benjamin,
How about base 2.
11 and 13, 23 and 29, 47 and 61, 191 and 253. And non prime 95 and 125.
There seems to be one in base 2.
formula is x(0)=5
x(n) = x(n1)*2+1
y(0)=5
y(n)=y(n1)*2+3
Can anyone extrapolate that when one is not prime then both are not prime?
