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%I #41 Dec 14 2023 06:06:04
%S 6,8,6,8,6,8,6,8,6,8,6,8,6,8,6,8,6,8,6,8,6,8,6,8,6,8,6,8,6,8,6,8,6,8,
%T 6,8,6,8,6,8,6,8,6,8,6,8,6,8,6,8,6,8,6,8,6,8,6,8,6,8,6,8,6,8,6,8,6,8,
%U 6,8,6,8,6,8,6,8,6,8,6,8,6
%N Period 2: repeat (6,8).
%C Decimal expansion of 68/99. - _David A. Corneth_, Oct 18 2016
%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (0,1).
%F a(n) = (-1)^(n+1)+7. - _Paolo P. Lava_, Oct 27 2006
%F G.f.: ( -6-8*x ) / ((x-1)*(1+x)). - _R. J. Mathar_, Nov 21 2011
%F a(0)=6, a(n) = 10 - eulerphi(a(n-1)) for n>0. - _Alexander R. Povolotsky_, Oct 16 2016
%t NestList[10 - EulerPhi@ # &, 6, 120] (* or *)
%t CoefficientList[Series[(-6 - 8 x)/((x - 1) (1 + x)), {x, 0, 120}], x] (* _Michael De Vlieger_, Oct 21 2016 *)
%o (PARI) a(n)=6+n%2*2 \\ _Charles R Greathouse IV_, Dec 08 2015
%Y Cf. A176401.
%K nonn,easy
%O 0,1
%A _N. J. A. Sloane_.
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