%I A121365
%S A121365 1,1,1,2,9,43,185,732,2737,9845,34449,118102,398585,1328607,4384393,
%T A121365 14348912,46633953,150663529,484275617,1549681962,4939611241,
%U A121365 15690529811,49686677721,156905298052,494251688849
%N A121365 a(n)=6*a(n-1)-9*a(n-2)+n+1.
%C A121365 Cf. A121968 a[n]=2*a[n-1]-a[n-2]+n+1.
%F A121365 a(n)=(36 + (n-4)*3^n + 9*n)/36, n=1,2,...
%F A121365 O.g.f.: -x*(-1+7*x-15*x^2+8*x^3)/((-1+x)^2*(3*x-1)^2). - R. J. Mathar 
               (mathar(AT)strw.leidenuniv.nl), Dec 10 2007
%t A121365 Table[(9*(n+4)+(n-4)*3^n)/36,{n,25}]
%Y A121365 Cf. A121968.
%Y A121365 Sequence in context: A162273 A092239 A132847 this_sequence A018960 A002310 
               A055728
%Y A121365 Adjacent sequences: A121362 A121363 A121364 this_sequence A121366 A121367 
               A121368
%K A121365 nonn
%O A121365 1,4
%A A121365 Zak Seidov (zakseidov(AT)yahoo.com), Sep 06 2006