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%I #37 Dec 14 2023 06:05:05
%S 2,8,2,8,2,8,2,8,2,8,2,8,2,8,2,8,2,8,2,8,2,8,2,8,2,8,2,8,2,8,2,8,2,8,
%T 2,8,2,8,2,8,2,8,2,8,2,8,2,8,2,8,2,8,2,8,2,8,2,8,2,8,2,8,2,8,2,8,2,8,
%U 2,8,2,8,2,8,2,8,2,8,2,8,2
%N Period 2: repeat (2,8).
%C This is the regular (simple) continued fraction for (2+sqrt(5))/2 = A176055. - Antonia Redondo Buitrago, Jul 30 2009
%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (0,1).
%F a(n) = -3*(-1)^n+5. - _Paolo P. Lava_, Oct 20 2006
%F G.f.: 2(1+4x)/((1-x)(1+x)). a(n) = 2*A010685(n). - _R. J. Mathar_, Oct 20 2008
%F a(n) = (A010674(n)+1)*2. - _Martin Ettl_, Nov 09 2012
%p A010698:=n->5-3*(-1)^n; seq(A010698(n), n=0..100); # _Wesley Ivan Hurt_, Mar 26 2014
%t Table[5-3(-1)^n, {n, 0, 100}] (* _Wesley Ivan Hurt_, Mar 26 2014 *)
%t PadRight[{},120,{2,8}] (* _Harvey P. Dale_, Oct 31 2016 *)
%o (Maxima) A010698(n):=if evenp(n) then 2 else 8$
%o makelist(A010698(n),n,0,30); /* _Martin Ettl_, Nov 09 2012 */
%o (PARI) a(n)=n%2*6+2 \\ _Charles R Greathouse IV_, Jun 11 2015
%K nonn,easy
%O 0,1
%A _N. J. A. Sloane_
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