Christian 19 January 2016 at 10:51 How can the last digit be 2, in base 10? Wouldn’t that make it divisible by 2 and therefore not prime?

Will 19 January 2016 at 14:50 Interesting note.Your formula for perfect numbers is off. Wikipedia says (changing notation to be able to type more easily)2^(pā1) * (2^p ā 1)Since 7 is a mersenne prime your formula would make 7*8 a perfect number when really it is 28 = 4 * 7 = 1 + 2 + 4 + 7 + 14

How can the last digit be 2, in base 10? Wouldn’t that make it divisible by 2 and therefore not prime?

Interesting note.

Your formula for perfect numbers is off. Wikipedia says (changing notation to be able to type more easily)

2^(pā1) * (2^p ā 1)

Since 7 is a mersenne prime your formula would make 7*8 a perfect number when really it is 28 = 4 * 7 = 1 + 2 + 4 + 7 + 14

Thanks. I was missing a “/2”.