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