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 A084104 #19 Feb 23 2024 07:27:36
%S A084104 1,4,7,7,4,1,1,4,7,7,4,1,1,4,7,7,4,1,1,4,7,7,4,1,1,4,7,7,4,1,1,4,7,7,
%T A084104 4,1,1,4,7,7,4,1,1,4,7,7,4,1,1,4,7,7,4,1,1,4,7,7,4,1,1,4,7,7,4,1,1,4,
%U A084104 7,7,4,1,1,4,7,7,4,1,1,4,7,7,4,1,1,4,7,7,4,1,1,4,7,7,4,1,1,4,7,7,4,1,1,4,7
%N A084104 A period 6 sequence.
%C A084104 Partial sums of A084103.
%H A084104 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (2,-2,1).
%F A084104 Euler transform of length 6 sequence [ 4, -3, -1, 0, 0, 1]. - _Michael Somos_, Nov 07 2006
%F A084104 G.f.: (1+x)^3/((1-x)(1+x^3)).
%F A084104 G.f.:(1+x)^2/((1-x)*(1-x+x^2)). - _Jaume Oliver Lafont_, Aug 27 2009
%o A084104 (PARI) {a(n)=[1, 4, 7, 7, 4, 1][n%6+1]}
%o A084104 (PARI) a(n)=2*sqrt(3)*sin((n+5)*Pi/3)+4 \\ _Jaume Oliver Lafont_, Aug 27 2009
%Y A084104 Cf. A084101, A007877.
%K A084104 easy,nonn
%O A084104 0,2
%A A084104 _Paul Barry_, May 15 2003