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A068928 Number of incongruent ways to tile a 3 X 2n room with 1x2 Tatami mats. At most 3 Tatami mats may meet at a point. 7
2, 2, 2, 4, 5, 9, 12, 21, 30, 51, 76, 127, 195, 322, 504, 826, 1309, 2135, 3410, 5545, 8900, 14445, 23256, 37701, 60813, 98514, 159094, 257608, 416325, 673933, 1089648, 1763581, 2852242, 4615823, 7466468, 12082291, 19546175, 31628466 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
R. J. Mathar, Paving rectangular regions with rectangular tiles,...., arXiv:1311.6135 [math.CO], Table 10.
FORMULA
For n >= 8, a(n) = a(n-1) + 2*a(n-2) - a(n-3) - a(n-5) - a(n-6).
O.g.f.: x(2-4x^2-x^4+x^6)/((1-x-x^2)(1-x^2-x^4)). a(n) = (A000045(n+1)+A053602(n+1))/2, n>1. [From R. J. Mathar, Aug 30 2008]
CROSSREFS
Cf. A068922 for total number of tilings, A068926 for more info.
Essentially the same as A001224.
Sequence in context: A024405 A230381 A082547 * A326025 A278502 A278501
KEYWORD
easy,nonn
AUTHOR
Dean Hickerson, Mar 11 2002
STATUS
approved

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Last modified March 28 08:22 EDT 2024. Contains 371236 sequences. (Running on oeis4.)