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A109014 a(n) = gcd(n,11). 4
11, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 11, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 11, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 11, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 11, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 11, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 11, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 11, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 11, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Table of n, a(n) for n=0..98.

FORMULA

a(n) = 1 + 10*[11|n], where [x|y] = 1 when x divides y, 0 otherwise.

a(n) = a(n-11).

Multiplicative with a(p^e, 11) = gcd(p^e, 11). - David W. Wilson, Jun 12 2005

Dirichlet g.f.: zeta(s)*(1+10/11^s). - R. J. Mathar, Apr 08 2011

a(n) = ((n-1) mod 2 + 1)*(10*floor(((n-1) mod 11)/10) + 1). - Gary Detlefs, Dec 28 2011

MATHEMATICA

GCD[Range[0, 100], 11] (* Harvey P. Dale, May 14 2022 *)

PROG

(Python)

from math import gcd

def a(n): return gcd(n, 11)

print([a(n) for n in range(99)]) # Michael S. Branicky, Nov 01 2021

CROSSREFS

Cf. A109004.

Sequence in context: A118135 A318671 A337335 * A268357 A321804 A321800

Adjacent sequences:  A109011 A109012 A109013 * A109015 A109016 A109017

KEYWORD

nonn,easy,mult

AUTHOR

Mitch Harris

STATUS

approved

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Last modified October 6 23:36 EDT 2022. Contains 357270 sequences. (Running on oeis4.)