# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/

Search: id:a354131
Showing 1-1 of 1

%I A354131 #16 May 18 2022 13:13:17
%S A354131 1,2,12,48,216,936,4104,17928,78408,342792,1498824,6553224,28652616,
%T A354131 125277192,547747272,2394904968,10471198536,45783025416,200176267464,
%U A354131 875226954888,3826738469448,16731577137672,73155162229704,319854949515144,1398495821923656
%N A354131 Number of tilings of a 2 X n rectangle using 2 X 2 and 1 X 1 tiles, right trominoes and dominoes.
%C A354131 Tiling algorithm see A351322.
%H A354131 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (3,6).
%F A354131 G.f.: (1 - x) / (1 - 3*x - 6*x^2).
%F A354131 a(n) = 3*a(n-1) + 6*a(n-2).
%e A354131 a(3)=48
%e A354131 Number of tilings without a 2 X 2 square: 44, see A353878.
%e A354131 Number of other tilings: 4
%e A354131    ___ _   ___ _   _ ___   _ ___
%e A354131   |   | | |   |_| | |   | |_|   |
%e A354131   |___|_| |___|_| |_|___| |_|___|
%o A354131 (Maxima), see A352589.
%Y A354131 Cf. A351322, A352589, A353878, A354130, A354132.
%K A354131 nonn,easy
%O A354131 0,2
%A A354131 _Gerhard Kirchner_, May 18 2022

# Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE