%I A080424
%S A080424 0,1,3,27,135,891,5103,31347,185895,1121931,6711903,40330467,241805655,
%T A080424 1451365371,8706597903,52244370387,313451873415,1880754287211,
%U A080424 11284396583103,67706766919107,406239439253175,2437440122303451
%N A080424 a(n)=3a(n-1)+18a(n-2), a(0)=0, a(1)=1.
%F A080424 G.f.: x/((1+3x)(1-6x)); a(n)=(6^n-(-3)^n)/9.
%Y A080424 Cf. A079773, A051958, A015441.
%Y A080424 Sequence in context: A161807 A063263 A034200 this_sequence A001796 A127509 
               A108142
%Y A080424 Adjacent sequences: A080421 A080422 A080423 this_sequence A080425 A080426 
               A080427
%K A080424 easy,nonn
%O A080424 0,3
%A A080424 Paul Barry (pbarry(AT)wit.ie), Feb 24 2003