%I A082841
%S A082841 3,9,33,123,459,1713,6393,23859,89043,332313,1240209,4628523,17273883,
%T A082841 64467009,240594153,897909603,3351044259,12506267433,46674025473,
%U A082841 174189834459,650085312363,2426151414993,9054520347609,33791929975443
%N A082841 a(n)=4a(n-1)-a(n-2).
%H A082841 <a href="Sindx_Rea.html#recLCC">Index entries for sequences related to 
               linear recurrences with constant coefficients</a>
%H A082841 Tanya Khovanova, <a href="http://www.tanyakhovanova.com/RecursiveSequences/
               RecursiveSequences.html">Recursive Sequences</a>
%F A082841 G.f.: (3-6x+3x^2)/((1-x)(1-4x+x^2)). With a=2+sqrt(3), b=2-sqrt(3): a(n)=sqrt(3/
               2)(a^(n+1/2)+b^(n+1/2)). a(n)=sqrt(3(11+12*A082840(n)+4*A082840(n)^2)). 
               a(n)=sqrt((3/2)(A003500(2n+1)+2)). a(n)-a(n-1)=6*A001353(n). a(n)=3 
               (mod 6)
%t A082841 CoefficientList[Series[(3-6 x+3 x^2)/((1-x)(1-4 x+x^2)), {x, 0, 25}], 
               x]
%Y A082841 First differences of A005320.
%Y A082841 Equals 3 * A001835(n+1).
%Y A082841 Sequence in context: A148995 A148996 A148997 this_sequence A151038 A039648 
               A049182
%Y A082841 Adjacent sequences: A082838 A082839 A082840 this_sequence A082842 A082843 
               A082844
%K A082841 easy,nonn
%O A082841 0,1
%A A082841 Mario Catalani (mario.catalani(AT)unito.it), Apr 14 2003