A104412 Number of prime factors, with multiplicity, of the pentanacci numbers A001591.

0, 0, 1, 2, 3, 4, 1, 1, 5, 3, 5, 6, 2, 4, 6, 5, 9, 6, 2, 2, 6, 4, 6, 7, 1, 3, 3, 6, 4, 7, 4, 2, 7, 3, 9, 7, 3, 2, 2, 8, 9, 8, 2, 4, 11, 7, 9, 7, 7, 2, 4, 5, 6, 7, 3, 2, 7, 7, 13, 8, 4, 5, 5, 6, 10, 5, 4, 7, 11, 7, 8, 9, 4, 5, 4, 8, 7, 8, 4, 5, 6, 5, 10, 12, 2, 4, 5, 9, 12, 11, 7, 4, 13

Offset: 4

Author

Jonathan Vos Post, Mar 05 2005

Keywords

• nonn

Comments

Prime pentanacci numbers (A105757) correspond to 1s in the sequence, semiprimes to 2, and so forth.

Links

• Amiram Eldar, Table of n, a(n) for n = 4..237
• (terms 4..124 from Charles R Greathouse IV) [offset adapted by _Georg Fischer_, Jan 04 2021]

Crossrefs

Cf. A001591, A001222, A104411.

Programs

Mathematica

PrimeOmega/@Drop[LinearRecurrence[{1,1,1,1,1},{0,0,0,0,1},100],4] (* Harvey P. Dale, Mar 30 2019 *)

Formula

a(n) = A001222(A001591(n)). a(n) = bigomega(A001591(n)).

Extensions

Offset corrected by Joerg Arndt, Dec 19 2020