login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A085035 Number of prime factors of cyclotomic(n,10), which is A019328(n), the value of the n-th cyclotomic polynomial evaluated at x=10. 3
2, 1, 2, 1, 2, 2, 2, 2, 2, 1, 2, 1, 3, 1, 2, 2, 2, 2, 1, 2, 3, 4, 1, 1, 3, 2, 3, 3, 5, 3, 3, 5, 2, 3, 3, 1, 3, 1, 1, 2, 4, 4, 4, 3, 2, 4, 2, 1, 2, 3, 4, 2, 4, 2, 4, 2, 3, 2, 2, 3, 7, 1, 5, 4, 2, 2, 3, 3, 3, 2, 2, 3, 3, 3, 3, 2, 4, 5, 6, 2, 6, 2, 3, 2, 3, 3, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The Mobius transform of this sequence yields A057951, number of prime factors of 10^n-1.

REFERENCES

See references at A085021.

LINKS

Ray Chandler, Table of n, a(n) for n = 1..322

Makoto Kamada, Factorizations of Phi_n(10)

FORMULA

a(n) = A001222(A019328(n)). - Ray Chandler, May 10 2017

MATHEMATICA

Table[Plus@@Transpose[FactorInteger[Cyclotomic[n, 10]]][[2]], {n, 1, 100}]

CROSSREFS

Cf. A001222, A019328, A057951, A085021.

Sequence in context: A219181 A260341 A109969 * A198333 A191591 A083023

Adjacent sequences:  A085032 A085033 A085034 * A085036 A085037 A085038

KEYWORD

nonn

AUTHOR

T. D. Noe, Jun 19 2003

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified February 21 03:06 EST 2019. Contains 320364 sequences. (Running on oeis4.)