cp's OEIS Frontend

A219970 Number of tilings of a 6 X n rectangle using straight (3 X 1) trominoes and 2 X 2 tiles.

%I A219970 #8 Dec 07 2012 12:52:47
%S A219970 1,1,2,8,21,65,267,804,2530,9407,29876,96530,337607,1100968,3612017,
%T A219970 12284181,40538721,133971666,450045654,1492504271,4949649998,
%U A219970 16537407509,54951656907,182545459254,608458757050,2023395434235,6727009100372,22399013790607
%N A219970 Number of tilings of a 6 X n rectangle using straight (3 X 1) trominoes and 2 X 2 tiles.
%H A219970 Alois P. Heinz, <a href="/A219970/b219970.txt">Table of n, a(n) for n = 0..600</a>
%e A219970 a(2) = 2, because there are 2 tilings of a 6 X 2 rectangle using straight (3 X 1) trominoes and 2 X 2 tiles:
%e A219970 ._._.   .___.
%e A219970 | | |   |   |
%e A219970 | | |   |___|
%e A219970 |_|_|   |   |
%e A219970 | | |   |___|
%e A219970 | | |   |   |
%e A219970 |_|_|   |___|
%Y A219970 Column k=6 of A219967.
%K A219970 nonn
%O A219970 0,3
%A A219970 _Alois P. Heinz_, Dec 02 2012