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.

First deviation from A259020 is at a(15).

With number 2 complement of A259023 with respect to A118369.

1 together with squarefree semiprimes (A006881) k such that k^2 + 1 is prime. Without the squarefree restriction there will be only one more term, 4. - Amiram Eldar, Sep 25 2022

The divisorial primes are primes of the form p = 1 + Product_{d|k} d = 1 + A007955(k) for some k.

Supersequence of A259021. Subsequence of A005574. First deviation from A259021 is at a(15).