A109014 - OEIS

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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

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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