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A368221
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Table read by antidiagonals downward: T(n,k) is the number of tilings of the n X k grid up to horizontal reflection by two tiles that are each fixed under horizontal reflection.
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4
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2, 4, 3, 8, 10, 6, 16, 36, 40, 10, 32, 136, 288, 136, 20, 64, 528, 2176, 2080, 544, 36, 128, 2080, 16896, 32896, 16640, 2080, 72, 256, 8256, 133120, 524800, 526336, 131328, 8320, 136, 512, 32896, 1056768, 8390656, 16793600, 8390656, 1050624, 32896, 272
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OFFSET
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1,1
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LINKS
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EXAMPLE
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Table begins:
n\k| 1 2 3 4 5 6
---+---------------------------------------------
1 | 2 4 8 16 32 64
2 | 3 10 36 136 528 2080
3 | 6 40 288 2176 16896 133120
4 | 10 136 2080 32896 524800 8390656
5 | 20 544 16640 526336 16793600 537001984
6 | 36 2080 131328 8390656 536887296 34359869440
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MATHEMATICA
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A368221[n_, m_] := 1/2 (2^(n*m) + If[EvenQ[n], 2^(n*m/2), 2^(m (n + 1)/2)])
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CROSSREFS
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KEYWORD
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AUTHOR
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STATUS
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approved
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