A249762 Number of tilings of a 5 X n rectangle using n pentominoes of shapes F, I, L.
1, 1, 3, 5, 13, 50, 133, 360, 875, 2254, 6336, 17331, 47199, 124476, 330344, 889454, 2400961, 6485476, 17392906, 46616158, 125153478, 336529923, 905611165, 2434088873, 6539233985, 17567977887, 47214493386, 126927551197, 341177175540, 916960655233
Offset: 0
Keywords
Examples
a(4) = 13: ._______. ._______. ._______. | | | | | | ._| ._| | | ._| | | | | | | | |_. | | | | | | | | | | | | | | |_| | | | | | | | | | | | |_| ._| | | |_| | | |_|_|_|_| (1) |___|___| (2) |_|___|_| (2) ._______. ._______. ._______. | ._| | | | ._| ._| | ._|_. | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |_| | | | |_| |_| | |_| | |_| |___|_|_| (4) |___|___| (2) |___|___| (2) .
Links
- Alois P. Heinz, Table of n, a(n) for n = 0..1000
- Vaclav Kotesovec, G.f. and the recurrence (of order 315)
- Wikipedia, Pentomino
Formula
a(n) ~ c * d^n, where d = 2.6877447474867836174937272605197376719631593933016281800670782370745298422..., c = 0.3236150736074998563483897952085529328299218049725560430481595704054051228... (1/d is the root of the denominator, see g.f.). - Vaclav Kotesovec, May 19 2015