A243648 Number of ways five L-tiles can be placed on an n X n square.

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

Offset: 0

Author

Alois P. Heinz, Jun 08 2014

Keywords

• nonn
• easy

Links

• Alois P. Heinz, Table of n, a(n) for n = 0..1000

Crossrefs

Column k=5 of A243608.

Programs

Maple

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);

Formula

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.