What comes next?

[John Keith]

(10-13-2024 06:33 PM)Geoff Quickfall Wrote:  Any perfect number algorithms out there?

Perfect numbers are easy (sort of). 2^(p-1)*(2^p - 1) is a perfect number if (2^p - 1) is a Mersenne prime. For example, 2^3-1 = 7 is prime and since 2^(3-1) = 4, 28 = 4*7 is a perfect number.
Of course now you need the ISPRIME? function, which limits you to the HP 49 or later unless you want to roll your own ISPRIME?.