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 A105395 #24 Jul 17 2024 19:13:21
%S A105395 1,1,1,7,1,1,7,1,1,7,1,1,7,1,1,7,1,1,7,1,1,7,1,1,7,1,1,7,1,1,7,1,1,7,
%T A105395 1,1,7,1,1,7,1,1,7,1,1,7,1,1,7,1,1,7,1,1,7,1,1,7,1,1,7,1,1,7,1,1,7,1,
%U A105395 1,7,1,1,7,1,1,7,1,1,7,1,1,7,1,1,7,1,1,7,1,1,7,1,1,7,1,1,7,1,1,7,1,1,7,1,1
%N A105395 A simple "Fractal Jump Sequence" (FJS).
%C A105395 See A105397 for definition of Fractal Jump Sequence.
%C A105395 a(n+2) = the digital root of the n-th centered hexagonal number (A003215). - _Colin Barker_, Jan 30 2015
%H A105395 Colin Barker, <a href="/A105395/b105395.txt">Table of n, a(n) for n = 1..1000</a>
%H A105395 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,1).
%F A105395 a(n) = a(n-3) for n>4. - _Colin Barker_, Jan 30 2015
%F A105395 G.f.: -x*(2*x+1)*(3*x^2-x+1) / ((x-1)*(x^2+x+1)). - _Colin Barker_, Jan 30 2015
%t A105395 PadRight[{1}, 100, {7, 1, 1}] (* _Paolo Xausa_, Jul 17 2024 *)
%o A105395 (PARI) Vec(-x*(2*x+1)*(3*x^2-x+1)/((x-1)*(x^2+x+1)) + O(x^100)) \\ _Colin Barker_, Jan 30 2015
%Y A105395 Cf. A003215, A105397, A003215.
%K A105395 base,easy,nonn
%O A105395 1,4
%A A105395 _Eric Angelini_, May 01 2005