A196468 - OEIS

%I #31 Apr 09 2024 08:09:18

%S 11,53,255,1231,5943,28695,138551,668983,3230135,15596471,75306423,

%T 363611575,1755671991,8477134263,40931225015,197633437111,

%U 954258648503,4607568342455,22247307963831,107419505225143,518667252755895,2504347031924151,12092057138720183

%N a(1)=11; a(n) = floor((2 + sqrt(8))*a(n-1)) for n > 1.

%C Contains only odd numbers.

%H Vincenzo Librandi, <a href="/A196468/b196468.txt">Table of n, a(n) for n = 1..150</a>

%H <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (5,0,-4).

%F G.f.: -x*(-11 + 2*x + 10*x^2) / ( (x-1)*(4*x^2 + 4*x - 1) ).

%F a(n) = (2 + 33*A057087(n) + 20*A057087(n-1))/14. - _R. J. Mathar_, Oct 04 2011

%t NestList[Floor[(2+Sqrt[8])#]&,11,30] (* or *) LinearRecurrence[{5,0,-4},{11,53,255},30] (* _Harvey P. Dale_, Nov 18 2013 *)

%o (Magma) I:=[11,53,255]; [n le 3 select I[n] else 5*Self(n-1)-4*Self(n-3): n in [1..30]]; // _Vincenzo Librandi_, Oct 05 2011

%Y Cf. A057087, A086843, A086844.

%K nonn,easy

%O 1,1

%A _Philippe Deléham_, Oct 02 2011