%I #18 Oct 30 2022 18:19:59
%S 1,1,21,85,747,4375,31387,202841,1382259,9167119,61643709,411595537,
%T 2758179839,18448963469,123518353059,826573277157,5532716266089,
%U 37028886137273,247839719105625,1658772577825883,11102227136885119
%N Number of ways to tile a 7 X n rectangle with 1 X 1 and 2 X 2 tiles.
%H <a href="/index/Rec#order_08">Index entries for linear recurrences with constant coefficients</a>, signature (3,30,-17,-138,85,116,-42,-32).
%F a(n) = 3a(n-1) + 30a(n-2) - 17a(n-3) - 138a(n-4) + 85a(n-5) + 116a(n-6) - 42a(n-7) - 32a(n-8). - Keith Schneider (kschneid(AT)bulldog.unca.edu), Apr 02 2006
%F G.f.: ( 1 -2*x -12*x^2 +9*x^3 +17*x^4 -6*x^5 -6*x^6 ) / ( 1 -3*x -30*x^2 +17*x^3 +138*x^4 -85*x^5 -116*x^6 +42*x^7 +32*x^8 ). - _Colin Barker_, Nov 29 2012
%Y Cf. A001045, A054854, A054855, A063650-A063654.
%Y Column k=7 of A245013.
%K nonn,easy
%O 0,3
%A _Reiner Martin_, Jul 23 2001