A219870 Number of tilings of a 7 X n rectangle using dominoes and straight (3 X 1) trominoes.

1, 3, 60, 1562, 29907, 707903, 15859323, 354859954, 8061851335, 181382499259, 4095897476480, 92476840837163, 2086314577400136, 47096964973772265, 1062921614745008697, 23989328157229264043, 541446343762904191567, 12220135872229640539724

Offset: 0

Author

Alois P. Heinz, Nov 30 2012

Keywords

• nonn

Examples

			a(1) = 3, because there are 3 tilings of a 7 X 1 rectangle using dominoes and straight (3 X 1) trominoes:
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Links

• Alois P. Heinz, Table of n, a(n) for n = 0..250

Crossrefs

Column k=7 of A219866.