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 A109010 #26 Oct 19 2019 03:20:32
%S A109010 7,1,1,1,1,1,1,7,1,1,1,1,1,1,7,1,1,1,1,1,1,7,1,1,1,1,1,1,7,1,1,1,1,1,
%T A109010 1,7,1,1,1,1,1,1,7,1,1,1,1,1,1,7,1,1,1,1,1,1,7,1,1,1,1,1,1,7,1,1,1,1,
%U A109010 1,1,7,1,1,1,1,1,1,7,1,1,1,1,1,1,7,1,1,1,1,1,1,7,1,1,1,1,1,1,7,1,1
%N A109010 a(n) = gcd(n,7).
%H A109010 <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,0,0,0,1).
%F A109010 a(n) = 1 + 6*[7|n], where [x|y] = 1 when x divides y, 0 otherwise.
%F A109010 a(n) = a(n-7).
%F A109010 Multiplicative with a(p^e, 7) = gcd(p^e, 7). - _David W. Wilson_, Jun 12 2005
%F A109010 From _R. J. Mathar_, Apr 04 2011: (Start)
%F A109010 Dirichlet g.f.: zeta(s)*(1 + 6/7^s).
%F A109010 G.f.: (-7 - x - x^2 - x^3 - x^4 - x^5 - x^6) / ((x-1)*(1 + x + x^2 + x^3 + x^4 + x^5 + x^6)). (End)
%F A109010 a(n) = 6*floor(((n-1) mod 7)/6) + 1. - _Gary Detlefs_, Dec 28 2011
%p A109010 A109010:=n->gcd(n,7): seq(A109010(n), n=0..150); # _Wesley Ivan Hurt_, Apr 27 2017
%t A109010 GCD[Range[0,100],7] (* or *) PadRight[{},120,{7,1,1,1,1,1,1}] (* _Harvey P. Dale_, Apr 26 2018 *)
%Y A109010 Cf. A109004.
%K A109010 nonn,easy,mult
%O A109010 0,1
%A A109010 _Mitch Harris_