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.

(In reply to Task 4 by Jer)

You prefer   "...that the list should start 1,2,3,4,6...

Posted by Ady TZIDON on 2018-02-18 14:28:28