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A103858 Number of distinct prime factors of prime(n)! - prime(n)# + 1. 2
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

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

LINKS

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

R. Zumkeller, p(n)!-p(n )#+1

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 *)

CROSSREFS

Cf. A001221, A103855, A103893.

Sequence in context: A320510 A117173 A241061 * A010554 A062610 A025801

Adjacent sequences:  A103855 A103856 A103857 * A103859 A103860 A103861

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Feb 20 2005

STATUS

approved

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Last modified October 27 00:02 EDT 2021. Contains 348270 sequences. (Running on oeis4.)