cp's OEIS Frontend

A divisorial prime is a prime p of the form p = 1 + Product_{d|k} d for some k (see A007955 and A258455).

Sequence lists divisorial primes p from A258455 such that p-1 = A007955(k) for some k < sqrt(p-1).

If 1 + Product_{d|k} d for some k > 1 is a prime p other than 3, then p-1 is a square and p is either of the form k^2 + 1 or h^2 + 1 where h>k. In this sequence are divisorial primes of the second kind. Divisorial primes of the first kind are in A258896.

With number 3, complement of A258896 with respect to A258455.

With numbers 2 and 3, divisorial primes p that are not of the form 4*q^2 + 1 where q = prime.

See A259023 - numbers n such that Product_{d|n} d is a divisorial prime from this sequence.

Sequence lists divisorial primes p from A258455 such that p-1 = A007955(sqrt(p-1)).

If 1 + Product_{d|k} d for some k > 1 is a prime p other than 3, then p-1 is a square and p is either of the form k^2 + 1 or h^2 + 1 where h>k. In this sequence are divisorial primes of the first kind. Divisorial primes of the second kind are in A258897.

With number 3, complement of A258897 with respect to A258455.

All terms > 2 are of the form 4*q^2 + 1 where q = prime (see A052292).

Subsequence of A002496 (primes of the form k^2 + 1), and the corresponding k are a subsequence of A007422. - Michel Marcus, Jul 09 2015