

A236584


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


1



1, 1, 1, 5, 11, 19, 45, 105, 219, 475, 1061, 2313, 5027, 11035, 24173, 52793, 115499, 252827, 552981, 1209545, 2646419, 5789563, 12664925, 27706873, 60614235, 132602171, 290087749, 634616521, 1388325507, 3037181147
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OFFSET

0,4


COMMENTS

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


LINKS



FORMULA

G.f.: (1x)/(4*x^3+12*x+x^2+2*x^4).


MAPLE

g := (1x)/(4*x^3+12*x+x^2+2*x^4) ;
taylor(%, x=0, 30) ;
gfun[seriestolist](%) ;


CROSSREFS



KEYWORD

easy,nonn


AUTHOR



STATUS

approved



