%I
%S 5,9,5,9,5,9,5,9,5,9,5,9,5,9,5,9,5,9,5,9,5,9,5,9,5,9,5,9,5,9,5,9,5,9,
%T 5,9,5,9,5,9,5,9,5,9,5,9,5,9,5,9,5,9,5,9,5,9,5,9,5,9,5,9,5,9,5,9,5,9,
%U 5,9,5,9,5,9,5,9,5,9,5,9,5
%N Period 2: repeat (5,9).
%C Continued fraction expansion of A176324.  _R. J. Mathar_, Mar 08 2012
%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (0,1).
%F a(n) = 2*(1)^n + 7 = 9*(n mod 2) + 5*[(n+1) mod 2].  _Paolo P. Lava_, Oct 20 2006
%F a(n) = a(n2) for n > 1; a(0) = 5, a(1) = 9. G.f.: (5+9*x)/((1x)*(1+x)).  _Vincenzo Librandi_, Aug 01 2010
%t Table[5 + 4 Mod[n, 2], {n, 0, 50}] (* _Jinyuan Wang_, Feb 26 2020 *)
%o (PARI) a(n)=n%2*4+5 \\ _Charles R Greathouse IV_, Jul 13 2016
%K nonn,easy
%O 0,1
%A _N. J. A. Sloane_
