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Number of tilings of a 6 X n rectangle using integer-sided rectangular tiles of equal area.
2

%I #12 Sep 05 2021 19:14:26

%S 1,4,21,54,343,1225,7104,31777,169952,819260,4234749,21008157,

%T 107087889,536982808,2721665059,13704483996,69301052416,349520578291,

%U 1765820428959,8911657997748,45005845549969,227191526564923,1147192132487813,5791672997769659

%N Number of tilings of a 6 X n rectangle using integer-sided rectangular tiles of equal area.

%C a(n+1)/a(n) tends to r = 5.048917339522305313522214407..., where r is the largest root of 1-5*x+6*x^2-x^3. - _Vaclav Kotesovec_, Dec 21 2012

%H Alois P. Heinz, <a href="/A220772/b220772.txt">Table of n, a(n) for n = 0..500</a>

%e a(1) = 4:

%e ._. ._. ._. ._.

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%Y Column k=6 of A220777.

%K nonn

%O 0,2

%A _Alois P. Heinz_, Dec 19 2012