login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A109015 a(n) = gcd(n,12). 5
12, 1, 2, 3, 4, 1, 6, 1, 4, 3, 2, 1, 12, 1, 2, 3, 4, 1, 6, 1, 4, 3, 2, 1, 12, 1, 2, 3, 4, 1, 6, 1, 4, 3, 2, 1, 12, 1, 2, 3, 4, 1, 6, 1, 4, 3, 2, 1, 12, 1, 2, 3, 4, 1, 6, 1, 4, 3, 2, 1, 12, 1, 2, 3, 4, 1, 6, 1, 4, 3, 2, 1, 12, 1, 2, 3, 4, 1, 6, 1, 4, 3, 2, 1, 12, 1, 2, 3, 4, 1, 6, 1, 4, 3, 2, 1, 12, 1, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,1
COMMENTS
Periodic, with period = 12. - Harvey P. Dale, Dec 20 2018
LINKS
FORMULA
a(n) = 1 + [2|n] + 2*[3|n] + 2*[4|n] + 2*[6|n] + 4*[12|n], where [x|y] = 1 when x divides y, 0 otherwise.
a(n) = a(n-12).
Multiplicative with a(p^e, 12) = gcd(p^e, 12). - David W. Wilson, Jun 12 2005
Dirichlet g.f.: zeta(s)*(1 + 1/2^s + 2/4^s)*(1 + 2/3^s). - R. J. Mathar, Apr 08 2011
MATHEMATICA
GCD[Range[0, 100], 12] (* or *) PadRight[{}, 120, {12, 1, 2, 3, 4, 1, 6, 1, 4, 3, 2, 1}] (* Harvey P. Dale, Dec 20 2018 *)
PROG
(Python)
from math import gcd
def a(n): return gcd(n, 12)
print([a(n) for n in range(99)]) # Michael S. Branicky, Dec 01 2021
CROSSREFS
Cf. A109004.
Sequence in context: A010211 A335503 A066786 * A010210 A361206 A229193
KEYWORD
nonn,easy,mult
AUTHOR
STATUS
approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 18 21:02 EDT 2024. Contains 370951 sequences. (Running on oeis4.)