%I #7 Sep 08 2013 13:31:47
%S 1,6,42,330,2778,24234,215034,1923018,17258010,155125482,1395342906,
%T 12554940426,112981880922,1016786596650,9150878043258,82357097082954,
%U 741210652521114,6670882987788138,60037895350485690,540340851995941002
%N a(0)=1, a(1)=6, a(n)=13*a(n-1)-36*a(n-2) for n>1.
%C a(n)/a(n-1) tends to 9.
%F G.f.: (1-7x)/(1-13x+36x^2). a(n)=Sum_{k, 0<=k<=n}A165253(n,k)*6^(n-k).
%F a(n) = (2*9^n+3*4^n)/5. [From _Klaus Brockhaus_, Sep 26 2009]
%K nonn
%O 0,2
%A _Philippe Deléham_, Sep 14 2009