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A227087
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Number of nX4 binary arrays indicating whether each 2X2 subblock of a larger binary array has lexicographically increasing rows and columns, for some larger (n+1)X5 binary array with rows and columns of the latter in lexicographically nondecreasing order
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1
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11, 62, 302, 1339, 5517, 21335, 77706, 267130, 868999, 2683571, 7894237, 22199557, 59882610, 155443180, 389435848, 944177113, 2220593929, 5077160511, 11307063564, 24570317758, 52177373347, 108436508850, 220822419206
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OFFSET
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1,1
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COMMENTS
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LINKS
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FORMULA
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Empirical: a(n) = (1/25852016738884976640000)*n^23 + (1/562000363888803840000)*n^22 + (1/8515157028618240000)*n^21 + (1/132703745900544000)*n^20 + (3011/14597412049059840000)*n^19 + (199/21341245685760000)*n^18 + (294787/1344498478202880000)*n^17 + (102919/15817629155328000)*n^16 + (1078127/11716762337280000)*n^15 + (62248451/22596613079040000)*n^14 + (2676107873/124281371934720000)*n^13 + (666103729/1274680737792000)*n^12 + (817147686029/316352583106560000)*n^11 + (124912409179/1797457858560000)*n^10 - (2789045615843/26362715258880000)*n^9 + (1628096767483/282457663488000)*n^8 - (543081878439151/48017802792960000)*n^7 + (42719702707217/250092722880000)*n^6 - (48939011143167373/177399104762880000)*n^5 + (390838159073513/147832587302400)*n^4 - (1242236984135201/542052820108800)*n^3 + (3097267852537/403313110200)*n^2 + (99388331/47805615)*n + 1
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EXAMPLE
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Some solutions for n=4
..0..1..0..0....0..1..1..0....0..1..1..0....0..0..0..0....0..0..0..0
..0..1..0..0....1..1..0..0....0..0..0..1....0..0..1..0....1..0..1..0
..0..0..1..0....0..0..1..0....1..1..0..0....1..0..1..0....1..0..0..0
..0..0..0..1....1..0..0..0....1..0..0..0....0..0..0..1....0..0..1..1
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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