A113913 Number of distinct prime factors of 3^(3^n)+1.

1, 2, 4, 6, 11, 20, 27

Offset

0,2

Comments

The term omega(3^(3^6)+1) was obtained with ECM factoring.

Links

Table of n, a(n) for n=0..6.

Formula

a(n) = A001221(A129290(n)).

Mathematica

Table[PrimeNu[3^(3^n) + 1], {n, 1, 10}] (* G. C. Greubel, May 16 2017 *)

Prog

(PARI) for(x=1, 6, print1( omega(3^(3^x)+1), ", "))

Crossrefs

Sequence in context: A000694 A164137 A018170 * A002097 A026757 A026385

Adjacent sequences: A113910 A113911 A113912 * A113914 A113915 A113916

Keyword

hard,more,nonn

Author

Jorge Coveiro, Jan 29 2006

Status

approved