%I A052929
%S A052929 2,3,10,27,82,243,730,2187,6562,19683,59050,177147,531442,1594323,
%T A052929 4782970,14348907,43046722,129140163,387420490,1162261467,3486784402,
%U A052929 10460353203,31381059610,94143178827,282429536482,847288609443
%N A052929 A simple regular expression.
%H A052929 INRIA Algorithms Project, <a href="http://algo.inria.fr/bin/encyclopedia?Search=ECSnb&argsearch=915">
               Encyclopedia of Combinatorial Structures 915</a>
%F A052929 G.f.: -(-2+3*x+x^2)/(-1+x^2)/(-1+3*x)
%F A052929 Recurrence: {a(1)=3, a(2)=10, a(0)=2, -3*a(n)-2*a(n+1)+a(n+2)+2}
%F A052929 3^n+Sum(1/2*_alpha^(-n), _alpha=RootOf(-1+_Z^2))
%p A052929 spec := [S,{S=Union(Sequence(Prod(Z,Z)),Sequence(Union(Z,Z,Z)))},unlabeled]: 
               seq(combstruct[count](spec, size=n), n=0..20);
%Y A052929 Sequence in context: A103018 A005158 A005225 this_sequence A151415 A134588 
               A000060
%Y A052929 Adjacent sequences: A052926 A052927 A052928 this_sequence A052930 A052931 
               A052932
%K A052929 easy,nonn
%O A052929 0,1
%A A052929 encyclopedia(AT)pommard.inria.fr, Jan 25 2000
%E A052929 More terms from James A. Sellers (sellersj(AT)math.psu.edu), Jun 05 2000