A247744 Total number of X shapes in all tilings of a 5 X n rectangle with pentominoes of any shape.
0, 0, 0, 1, 8, 76, 752, 7728, 76138, 683740, 6016612, 52483260, 453461612, 3873299197, 32718505462, 274368261226, 2287565667766, 18973561019204, 156622182476404, 1287479429817295, 10545476231546336, 86101164740284870, 700977394316933694, 5692064258367318333
Offset: 0
Keywords
Links
- Alois P. Heinz, Table of n, a(n) for n = 0..500
- Wikipedia, Pentomino
Formula
a(n) = Sum_{k>0} k * A247711(n,k).