Definition: Strictly non-palindromic number or SNP number n is a number not palindromic in any base b with 2 ≤ b ≤ n-2.

Equipped only with the above definition you are asked to perform the following tasks:
1. Show that 47 is a SNP number.
2. Write down the 1st 7 members of an increasing sequence of SNP numbers.
3. Explain the reason for defining b=n-2 as the upper limit.
4. Prove that all SNP numbers above 6 are prime, but not all primes are SNP numbers.

To be SNP a number must be prime, otherwise, it will look like aa in some base:

Posted by Jer on 2018-02-18 13:12:25