%I #8 Jun 13 2015 00:54:57

%S 1,1,1,5,11,19,45,105,219,475,1061,2313,5027,11035,24173,52793,115499,

%T 252827,552981,1209545,2646419,5789563,12664925,27706873,60614235,

%U 132602171,290087749,634616521,1388325507,3037181147

%N The number of tilings of a 9 X (2n) floor with 2 X 3 hexominoes.

%C Tilings are counted irrespective of internal symmetry: Tilings that match each other after rotations and/or reflections are counted with their multiplicity.

%H R. J. Mathar, <a href="http://arxiv.org/abs/1311.6135">Paving rectangular regions...</a>, arXiv:1311.6135, Table 52.

%H R. J. Mathar, <a href="http://arxiv.org/abs/1406.7788">Tilings of Rectangular Regions by Rectangular Tiles: Counts Derived from Transfer Matrices</a>, arXiv:1406.7788 [math.CO], eq. (35).

%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1,4,-2).

%F G.f.: (1-x)/(-4*x^3+1-2*x+x^2+2*x^4).

%p g := (1-x)/(-4*x^3+1-2*x+x^2+2*x^4) ;

%p taylor(%,x=0,30) ;

%p gfun[seriestolist](%) ;

%Y Cf. A000079 (5Xn floor), A182097 (6Xn floor), A000244 (7Xn floor), A236583 (8X3n floor)

%K easy,nonn

%O 0,4

%A _R. J. Mathar_, Jan 29 2014