A181186 Number of prime factors of (2^n - 1) * n! + 1, counted with multiplicity.

1, 1, 1, 2, 2, 1, 3, 3, 2, 2, 3, 2, 3, 5, 3, 2, 1, 3, 2, 2, 3, 3, 2, 6, 1, 4, 4, 3, 3, 3, 2, 2, 4, 3, 5, 2, 4, 2, 4, 1, 4, 4, 3, 3, 1, 3, 4, 5, 3, 4, 4, 5, 2, 2, 2, 6, 4, 2, 5, 3, 7, 4, 3, 2, 5, 3, 4, 4, 4, 2, 7, 6, 7, 3, 5, 2, 4, 3, 8, 8, 6, 4

Offset

1,4

Comments

a(101) >= 3. See link to factordb.com. - Hugo Pfoertner, Aug 07 2019

Links

Yurii Ivanov, Table of n, a(n) for n = 1..103 (terms 1..100 from Sean A. Irvine and Hugo Pfoertner, term 101 from Tyler Busby)

Sean A. Irvine, Factorizations of (2^n-1)*n!+1

factordb.com, Status of (2^n-1)*n!+1.

Formula

a(n) = A001222(A052589(n)+1). - Michel Marcus, Apr 08 2023

Mathematica

Table[PrimeOmega[(2^n-1)n!+1], {n, 90}] (* The program takes a long time to run. *) (* Harvey P. Dale, Feb 10 2019 *)

Crossrefs

Cf. A001222, A052589.

Sequence in context: A193739 A345032 A182535 * A364197 A097291 A269501

Adjacent sequences: A181183 A181184 A181185 * A181187 A181188 A181189

Keyword

nonn

Author

Jason Earls, Oct 09 2010

Extensions

More terms from Sean A. Irvine, Sep 15 2012

Status

approved