%I A145073
%S A145073 1,2,7,44,325,3110,34258,436304,6246439,99637730,1747851787,33469239848,
%T A145073 694321125511
%N A145073 a(n) = [x^(3^n)] Q(x,n)^(n+1) where Q(x,n) = Sum_{k=0..n} (x^(3^k) + 
               x^(2*3^k)) for n>=0.
%e A145073 a(n) equals the coefficient of x^(3^n) in Q(x,n)^(n+1) where
%e A145073 Q(x,n) = Sum_{k=0..n} (x^(3^k) + x^(2*3^k)) for n>=0.
%o A145073 (PARI) {a(n)=local(Q=sum(j=0,n,x^(3^j)+x^(2*3^j)+O(x^(3^n+1))));polcoeff(Q^(n+1),
               3^n)}
%Y A145073 Cf. A007178, A145074, A145075, A145076.
%Y A145073 Sequence in context: A103084 A041507 A158107 this_sequence A111561 A000155 
               A077045
%Y A145073 Adjacent sequences: A145070 A145071 A145072 this_sequence A145074 A145075 
               A145076
%K A145073 more,nonn
%O A145073 0,2
%A A145073 Paul D. Hanna (pauldhanna(AT)juno.com), Oct 09 2008
%E A145073 a(10) - a(12) from Alois P. Heinz (heinz(AT)hs-heilbronn.de), Apr 28 
               2009