A103858 Number of distinct prime factors of prime(n)! - prime(n)# + 1.

0, 0, 2, 1, 2, 2, 2, 2, 4, 2, 3, 4, 4, 5, 5, 3, 5, 3, 4, 6, 5, 4, 5, 6, 9, 1

Offset

1,3

Comments

a(27) >= 4. - Amiram Eldar, Jan 21 2024

Links

Table of n, a(n) for n=1..26.

Factordb.com, Status of 103!-103#+1.

Reinhard Zumkeller, prime(n)!-prime(n)#+1.

Formula

a(n) = A001221(A103855(n)).

Mathematica

primorial[n_] := Product[Prime[i], {i, n}]; A103855[n_] := Prime[n]! - primorial[n] + 1;  PrimeNu[Array[A103855, 20]] (* G. C. Greubel, May 09 2017 *)

Prog

(PARI) a(n) = omega(prime(n)! - prod(k=1, n, prime(k)) + 1); \\ Michel Marcus, Nov 06 2022

Crossrefs

Cf. A001221, A103855, A103893.

Sequence in context: A320510 A117173 A241061 * A010554 A062610 A351593

Adjacent sequences: A103855 A103856 A103857 * A103859 A103860 A103861

Keyword

nonn,more

Author

Reinhard Zumkeller, Feb 20 2005

Status

approved