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A108550
Number of ways of packing a 3 X (2n-1) rectangle with dominoes, leaving one space unoccupied.
0
2, 18, 160, 1530, 14800, 143386, 1389432, 13464130, 130472968, 1264337250, 12251953552, 118726523722, 1150509376512, 11148914193898, 108037613809384, 1046929395512082, 10145181113692600, 98311022950389682
OFFSET
1,1
FORMULA
G.f.: 2*x*(1+x-x^2)*(1-4*x+x^2)/((1-10*x+3*x^2)*(1-x)^2).
CROSSREFS
Cf. A001835.
Sequence in context: A052838 A052876 A121933 * A322282 A270369 A352654
KEYWORD
easy,nonn
AUTHOR
Frans Clauwens (F.Clauwens(AT)science.ru.nl), Jun 09 2005
STATUS
approved