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A060312
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Number of distinct ways to cover a 2xn rectangle with dominoes (solutions are identified if they are rotations or reflections of each other).
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3
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1, 1, 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; internal format)
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OFFSET
| 1,3
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FORMULA
| If F(n) is the n-th Fibonacci number, then a(2n)=(F(2n)+F(n+1))/2 and a(2n+1)=(F(2n+1)+F(n))/2 for n>1.
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EXAMPLE
| a(3)=2 because of the configurations |= and |||
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CROSSREFS
| Essentially same as A001224, which is the main entry for this sequence.
Sequence in context: A039898 A083690 A144121 * A068372 A068370 A060167
Adjacent sequences: A060309 A060310 A060311 * A060313 A060314 A060315
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KEYWORD
| easy,nonn
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AUTHOR
| Thomas Ward (t.ward(AT)uea.ac.uk), Mar 27 2001
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