This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A109014 #23 May 14 2022 18:54:55 %S A109014 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, %T A109014 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, %U A109014 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 %N A109014 a(n) = gcd(n,11). %F A109014 a(n) = 1 + 10*[11|n], where [x|y] = 1 when x divides y, 0 otherwise. %F A109014 a(n) = a(n-11). %F A109014 Multiplicative with a(p^e, 11) = gcd(p^e, 11). - _David W. Wilson_, Jun 12 2005 %F A109014 Dirichlet g.f.: zeta(s)*(1+10/11^s). - _R. J. Mathar_, Apr 08 2011 %F A109014 a(n) = ((n-1) mod 2 + 1)*(10*floor(((n-1) mod 11)/10) + 1). - _Gary Detlefs_, Dec 28 2011 %t A109014 GCD[Range[0,100],11] (* _Harvey P. Dale_, May 14 2022 *) %o A109014 (Python) %o A109014 from math import gcd %o A109014 def a(n): return gcd(n, 11) %o A109014 print([a(n) for n in range(99)]) # _Michael S. Branicky_, Nov 01 2021 %Y A109014 Cf. A109004. %K A109014 nonn,easy,mult %O A109014 0,1 %A A109014 _Mitch Harris_