How many perfect numbers + 1 are prime
 

I noticed that some primes are of the form (perfect number + 1), while some P.N. + 1 are not prime. Has anybody looked at checking the primarily of (P.N. + 1)?

See [url]http://oeis.org/A061644[/url] .

[QUOTE=UoPTucson;536108]I noticed that some primes are of the form (perfect number + 1), while some P.N. + 1 are not prime. Has anybody looked at checking the primarily of (P.N. + 1)?[/QUOTE]

If we [i]assume[/i] that Sam Wagstaff's analysis of the distribution of Mersenne primes
is correct, we should expect finitely many.

See post #10 here:
[url]https://www.mersenneforum.org/showthread.php?t=10336[/url]

So far 4 primes and 1 unknown in the 51 known perfect numbers + 1.