%I #45 Aug 04 2024 22:05:24
%S 3,5,3,5,3,5,3,5,3,5,3,5,3,5,3,5,3,5,3,5,3,5,3,5,3,5,3,5,3,5,3,5,3,5,
%T 3,5,3,5,3,5,3,5,3,5,3,5,3,5,3,5,3,5,3,5,3,5,3,5,3,5,3,5,3,5,3,5,3,5,
%U 3,5,3,5,3,5,3,5,3,5,3,5,3,5,3,5,3,5,3,5
%N Period 2: repeat (3,5).
%C From _Klaus Brockhaus_, Dec 10 2009: (Start)
%C Interleaving of A010701 and A010716.
%C Also continued fraction expansion of (15+sqrt(285))/10.
%C Also decimal expansion of 35/99.
%C Binomial transform of 3 followed by A084633 without initial terms 1,0.
%C Inverse binomial transform of A171497. (End)
%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (0,1).
%F From _Klaus Brockhaus_, Dec 10 2009: (Start)
%F a(n) = a(n-2) for n > 1; a(0) = 3, a(1) = 5.
%F G.f.: (3+5*x)/((1-x)*(1+x)). (End)
%F a(n) = 4 - (-1)^n. - _Aaron J Grech_, Aug 02 2024
%F E.g.f.: 3*cosh(x) + 5*sinh(x). - _Stefano Spezia_, Aug 04 2024
%t Table[If[OddQ[n], 3, 5], {n, 1, 50}] (* _Stefan Steinerberger_, Apr 10 2006 *)
%t PadRight[{},120,{3,5}] (* _Harvey P. Dale_, Sep 03 2012 *)
%o (Magma) &cat[ [3, 5]: n in [1..53] ]; // _Klaus Brockhaus_, Dec 10 2009
%o (PARI) a(n)=3+n%2*2 \\ _Charles R Greathouse IV_, Nov 20 2011
%Y Cf. A010701 (all 3's sequence), A010716 (all 5's sequence), A084633 (inverse binomial transform of repeated odd numbers), A171497.
%K nonn,easy
%O 0,1
%A _N. J. A. Sloane_