%I A133673
%S A133673 7,18,40,83,163,311,579,1060,1914,3419,6053,10637,18575,32262,55772,
%T A133673 96019,164711,281635,480171,816536
%N A133673 a(n) = n*L(n) + (n-1)*L(n-1) where L(n) is the Lucas number.
%C A133673 For n>2, two evens followed by four odds.
%F A133673 G.f.: -x^2*(-7-4*x+3*x^2+x^3)/(x^2+x-1)^2. a(n)=2*a(n-1)+a(n-2)-2*a(n-3)-a(n-4). 
               a(n)=A146005(n)+A146005(n-1). [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), 
               Jul 08 2009, Jul 13 2009]
%e A133673 If n=2 then a(n) = 7
%e A133673 If n=21 then a(n) = 816536
%Y A133673 Cf. A000032, A136376.
%Y A133673 Sequence in context: A156619 A033537 A000566 this_sequence A023166 A002764 
               A124053
%Y A133673 Adjacent sequences: A133670 A133671 A133672 this_sequence A133674 A133675 
               A133676
%K A133673 nonn
%O A133673 2,1
%A A133673 Parthasarathy Nambi (PachaNambi(AT)yahoo.com), Dec 29 2007
%E A133673 Typo in A-numbers corrected by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), 
               Jul 13 2009