%I A056124
%S A056124 1,11,40,117,319,848,2233,5859,15352,40205,105271,275616,721585,
%T A056124 1889147,4945864,12948453,33899503,88750064,232350697,608302035,
%U A056124 1592555416,4169364221,10915537255,28577247552,74816205409
%N A056124 a(n)=3a(n-1)-a(n-2)+8; a(0)=1, a(1)=11.
%F A056124 a(n)={{19*[((3+sqrt(5))/2)^n - ((3-sqrt(5))/2)^n]-9*[((3+sqrt(5))/2)^(n-1) 
               - ((3-sqrt(5))/2)^(n-1)]}/sqrt(5)} - 8.
%F A056124 G.f.(x)=(1+7x)/(1-x)(1-3x+x^2).
%F A056124 Fibonacci(2n+5) + 2*Lucas(2n) - 8.
%Y A056124 Cf. A055850.
%Y A056124 Sequence in context: A147296 A059142 A064798 this_sequence A064768 A135719 
               A089776
%Y A056124 Adjacent sequences: A056121 A056122 A056123 this_sequence A056125 A056126 
               A056127
%K A056124 easy,nonn
%O A056124 0,2
%A A056124 Barry E. Williams, Jul 07 2000