Primitive semiperfect number
In
mathematics, a
primitive semiperfect number (also called a
primitive pseudoperfect number,
irreducible semiperfect number or
irreducible pseudoperfect number) is a
natural number that has no
semiperfect proper
divisor. The first few primitive semiperfect numbers are 6, 20, 28, 88, 104, 272, 304, 350, ... (
Sloane's
A006036).
It has been shown that there exist infinitely many odd primitive semiperfect numbers, as well as infinitely many primitive semiperfect numbers that are not harmonic divisor numbers.
Also see
External links