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A243648
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Number of ways five L-tiles can be placed on an n X n square.
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2
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0, 0, 0, 0, 0, 46, 4431, 73098, 587149, 3125278, 12712329, 42731866, 124522115, 324628878, 773900299, 1714106922, 3569586561, 7053577342, 13321444117, 24185953530, 42413141575, 72121174766, 119308962279, 192546161866, 303861667221, 469873699038, 713211276481
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OFFSET
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0,6
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LINKS
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FORMULA
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G.f.: x^5*(33*x^10 -293*x^9 +504*x^8 +1350*x^7 -3422*x^6 -7274*x^5 +28906*x^4 -19186*x^3 -26887*x^2 -3925*x -46) / (x-1)^11.
a(n) = (n^10 -10*n^9 -25*n^8 +520*n^7 -435*n^6 -9982*n^5 +19925*n^4 +82740*n^3 -215906*n^2 -244868*n +728760) / 120 for n>=5, a(n) = 0 for n<5.
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MAPLE
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a:= n-> `if`(n<5, 0, ((((((((((n-10)*n-25)*n+520)*n-435)*n
-9982)*n+19925)*n+82740)*n-215906)*n-244868)*n+728760)/120):
seq(a(n), n=0..40);
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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