A069464 Number of distinct prime factors of prime(n)^n+1.

1, 2, 3, 2, 3, 4, 3, 3, 6, 4, 3, 4, 6, 7, 6, 3, 4, 9, 4, 7, 9, 6, 7, 7, 7, 5, 10, 5, 8, 11, 7, 5, 11, 8, 11, 11, 6, 6, 10, 8, 9, 9, 4, 7, 16, 4, 7, 10, 9, 6, 14, 7, 4, 11, 13, 9, 11, 9, 3, 8, 9, 7, 18, 6, 17, 14, 5, 7, 12, 14, 8, 15, 6, 13, 18, 8, 18, 14, 5, 10, 15, 9

Offset

1,2

Links

Table of n, a(n) for n=1..82.

Dario Alpern, Factorization using the Elliptic Curve Method.

FactorDB, Status of 431^83+1.

Formula

a(n) = A001221(A062006(n)).

Example

A000040(10)^10+1 = 29^10+1 = 420707233300202 = 2*421*1061*470925821, therefore a(10) = 4 and A069465(10) = 4.

Mathematica

Table[PrimeNu[Prime[n]^n + 1], {n, 1, 50}] (* G. C. Greubel, May 08 2017 *)

Prog

(PARI) a(n) = omega(prime(n)^n+1); \\ Michel Marcus, Feb 17 2020

Crossrefs

Cf. A001221, A062006, A069461, A069465.

Sequence in context: A325811 A324380 A123182 * A156723 A240834 A256993

Adjacent sequences: A069461 A069462 A069463 * A069465 A069466 A069467

Keyword

nonn

Author

Reinhard Zumkeller, Mar 24 2002

Extensions

More terms from Hugo Pfoertner, May 21 2004

a(36) corrected and a(46)-a(82) added using factordb.com by Amiram Eldar, Feb 17 2020

Status

approved