%I A080041
%S A080041 1,2,7,20,55,152,415,1136,3103,8480,23167,63296,172927,472448,1290751,
%T A080041 3526400,9634303,26321408,71911423,196465664,536754175,1466439680,
%U A080041 4006387711,10945654784,29904084991,81699479552,223207129087
%N A080041 a(n)=floor((1+sqrt(3))^n).
%C A080041 a(n)=A080040(n)-(1+(-1)^n)/2
%F A080041 G.f.: g(t)=(1+2t^3)/(1-2t-3t^2+2t^3+2t^4)
%t A080041 CoefficientList[Series[(1+2t^3)/(1-2t-3t^2+2t^3+2t^4), {t, 0, 30}], t]
%Y A080041 Sequence in context: A035508 A018033 A000149 this_sequence A049681 A027120 
               A094982
%Y A080041 Adjacent sequences: A080038 A080039 A080040 this_sequence A080042 A080043 
               A080044
%K A080041 easy,nonn
%O A080041 0,2
%A A080041 Mario Catalani (mario.catalani(AT)unito.it), Jan 21 2003