A109014 a(n) = gcd(n,11).

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

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