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A104415 Number of prime factors, with multiplicity, of the nonzero octanacci numbers A079262. 1
0, 0, 1, 2, 3, 4, 5, 6, 7, 3, 1, 4, 5, 6, 6, 11, 7, 9, 1, 4, 3, 6, 8, 7, 8, 11, 10, 2, 2, 8 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

COMMENTS

Prime octanacci numbers: a(3) = 2, a(11) = 509, a(19) = 128257, ... Semiprime octanacci numbers: a(4) = 4 = 2^2, a(28) = 64504063 = 13 * 4961851, a(29) = 128752121 = 1093 * 117797.

LINKS

Table of n, a(n) for n=0..29.

FORMULA

a(n) = A001222(A079262(n)), offset to start with first nonzero value. a(n) = bigomega(A079262(n)), offset to start with first nonzero value.

EXAMPLE

a(0)=a(1)=0 because the first two nonzero octanacci numbers are both 1, which has zero prime divisors.

a(2)=1 because the 3rd nonzero octanacci number is 2, a prime, with only one prime divisor.

a(3)=2 because the 4th nonzero octanacci number is 4 = 2^2 which has (with multiplicity) 2 prime divisors (which happen to be equal).

a(4)=3 because the 5th nonzero octanacci number is 8 = 2^3.

a(10)= 3 because A079262(10) = 255 = 3 * 5 * 17 which has 3 prime factors.

CROSSREFS

Cf. A001222, A079262, A104411, A104412, A104413, A104414.

Sequence in context: A091733 A066990 A097449 * A071074 A279648 A066323

Adjacent sequences:  A104412 A104413 A104414 * A104416 A104417 A104418

KEYWORD

easy,nonn

AUTHOR

Jonathan Vos Post, Mar 06 2005

STATUS

approved

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Last modified May 20 12:33 EDT 2019. Contains 323422 sequences. (Running on oeis4.)