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%I #18 Aug 13 2023 08:50:16
%S 1,2,6,12,26,61,134,297,669,1490,3321,7426,16573,36986,82594,184382,
%T 411599,918931,2051485,4579826,10224441,22825825,50957971,113762629,
%U 253972415,566987102,1265785592,2825836529,6308612558,14083828826,31441815085,70193107041,156704451838,349838982690
%N Number of order-3 ribbon tilings for a 3 X n strip.
%C a(n) is the number of order-3 ribbon tilings of a 3 X n strip. Note that the width of the strip is equal to the order of ribbon tiles.
%D Yinsong Chen and Vladislav Kargin, The Number of ribbon tilings for strips, Discrete Applied Mathematics, Volume 340, 15 December 2023, pages 85-103.
%H Yinsong Chen, <a href="/A364423/b364423.txt">Table of n, a(n) for n = 1..100</a>
%H Yinsong Chen and Vladislav Kargin, <a href="https://arxiv.org/abs/2307.00767">The Number of ribbon tilings for strips</a>, arXiv:2307.00767 [math.CO], 2023.
%K nonn
%O 1,2
%A _Yinsong Chen_, Jul 26 2023