OFFSET
0,4
COMMENTS
Number of tilings of a 3 X n rectangle with 1 X 1 squares and L-shaped tiles (where the L-shaped tile covers 5 squares).
LINKS
Index entries for linear recurrences with constant coefficients, signature (1,0,4,2,2).
FORMULA
G.f.: 1/(1-x-4*x^3-2*x^4-2*x^5). - R. J. Mathar, Sep 03 2020
Sum_{k=0..n} a(k) = (a(n+3)+4*a(n)+2*a(n-1)-1)/8. - Sujay Champati, Sep 05 2020
EXAMPLE
Here is one of the 11 ways to tile a 3 X 4 rectangle:
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MATHEMATICA
LinearRecurrence[{1, 0, 4, 2, 2}, {1, 1, 1, 5, 11}, 50]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Sujay Champati and Greg Dresden, Aug 29 2020
STATUS
approved