A108550 Number of ways of packing a 3 X (2n-1) rectangle with dominoes, leaving one space unoccupied.

2, 18, 160, 1530, 14800, 143386, 1389432, 13464130, 130472968, 1264337250, 12251953552, 118726523722, 1150509376512, 11148914193898, 108037613809384, 1046929395512082, 10145181113692600, 98311022950389682

Offset

1,1

Links

Table of n, a(n) for n=1..18.

Formula

G.f.: ( (2x)(1+x-x^2)(1-4x+x^2))/((1-10x+3x^2)(1-x)^2))

Crossrefs

Cf. A001835.

Sequence in context: A052838 A052876 A121933 * A322282 A270369 A352654

Adjacent sequences: A108547 A108548 A108549 * A108551 A108552 A108553

Keyword

easy,nonn

Author

Frans Clauwens (F.Clauwens(AT)science.ru.nl), Jun 09 2005

Status

approved