A238265 Primes p such that p + 1 or p - 1 is in A055462.

2, 3, 23, 6911, 238878721, 5944066965503999

Offset

1,1

Comments

Primes which are within 1 of a superduperfactorial number.

Supersequence of A193430.

Links

Table of n, a(n) for n=1..6.

Formula

a(n) are the prime values of 1! * (1! * 2!) * (1! * 2! * 3!) * (1! * 2! * 3! * n!) +/- 1.

Example

A000142(2)^3*A000142(3)^2*A000142(4) - 1 = 6911, which is prime.

Prog

(PARI) t=1; p=1; for(n=1, 6, t*=n!; p*=t; if(isprime(p-1), print1(p-1, ", ")); if(isprime(p+1), print1(p+1, ", ")));

Crossrefs

Cf. A000142, A055462.

Sequence in context: A225726 A076530 A360225 * A203015 A260420 A241661

Adjacent sequences: A238262 A238263 A238264 * A238266 A238267 A238268

Keyword

nonn,hard

Author

Arkadiusz Wesolowski, Feb 21 2014

Status

approved