I'm looking for composite $n$ such that $\sigma(n)\equiv n+1\pmod{\varphi(n)}$
Are there only finitely many? Can this be proved?
This is Sloane's A070037 but there's not much information in the entry.
I'm looking for composite $n$ such that $\sigma(n)\equiv n+1\pmod{\varphi(n)}$
Are there only finitely many? Can this be proved?
This is Sloane's A070037 but there's not much information in the entry.