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A085028 Number of prime factors of cyclotomic(n,3), which is A019321(n), the value of the n-th cyclotomic polynomial evaluated at x=3. 1
1, 2, 1, 2, 2, 1, 1, 2, 1, 1, 2, 1, 1, 1, 1, 3, 2, 2, 2, 2, 1, 2, 2, 1, 2, 1, 3, 2, 3, 2, 3, 2, 1, 3, 2, 1, 2, 2, 4, 1, 3, 3, 2, 2, 3, 1, 4, 3, 5, 2, 2, 2, 3, 2, 3, 2, 3, 3, 2, 1, 2, 2, 1, 2, 3, 2, 3, 2, 2, 1, 1, 1, 4, 3, 3, 2, 3, 4, 3, 2, 3, 2, 4, 2, 2, 1, 3, 3, 3, 2, 2, 2, 2, 3, 2, 2, 3, 2, 2, 4 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

The Mobius transform of this sequence yields A057958, number of prime factors of 3^n-1.

REFERENCES

See references at A085021

LINKS

Table of n, a(n) for n=1..100.

MATHEMATICA

Table[Plus@@Transpose[FactorInteger[Cyclotomic[n, 3]]][[2]], {n, 1, 100}]

CROSSREFS

Cf. A019321, A057958, A085021.

Sequence in context: A304274 A081592 A255934 * A087888 A296299 A109494

Adjacent sequences:  A085025 A085026 A085027 * A085029 A085030 A085031

KEYWORD

nonn

AUTHOR

T. D. Noe, Jun 19 2003

STATUS

approved

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Last modified September 28 08:33 EDT 2020. Contains 337394 sequences. (Running on oeis4.)