%I A083423
%S A083423 1,2,9,18,81,162,729,1458,6561,13122,59049,118098,531441,1062882,
%T A083423 4782969,9565938,43046721,86093442,387420489,774840978,3486784401,
%U A083423 6973568802,31381059609,62762119218,282429536481,564859072962
%N A083423 (5*3^n+(-3)^n)/6.
%F A083423 G.f.: (1+2x)/((1-3x)(1+3x)). E.g.f.: (5exp(3x)+exp(-3x))/6
%Y A083423 Cf. A083424.
%Y A083423 Sequence in context: A028881 A083708 A037421 this_sequence A068978 A006226 
               A109298
%Y A083423 Adjacent sequences: A083420 A083421 A083422 this_sequence A083424 A083425 
               A083426
%K A083423 easy,nonn
%O A083423 0,2
%A A083423 Paul Barry (pbarry(AT)wit.ie), Apr 30 2003