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A224053
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Number of n X 4 0..2 arrays with rows and columns unimodal and antidiagonals nondecreasing.
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1
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46, 698, 5219, 27246, 115716, 428949, 1442005, 4492529, 13133871, 36307595, 95412314, 239342404, 575169570, 1328404782, 2957341785, 6363295591, 13266197675, 26858140315, 52913319943, 101631438086, 190636635796
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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) = (1/106748928000)*n^16 + (1/2668723200)*n^15 + (29/2335132800)*n^14 + (9677/37362124800)*n^13 + (129359/28740096000)*n^12 + (171629/2874009600)*n^11 + (12139/18662400)*n^10 + (195851/37324800)*n^9 + (231935077/5225472000)*n^8 + (74110763/261273600)*n^7 + (324341569/179625600)*n^6 + (4052978161/718502400)*n^5 + (3589053277/247104000)*n^4 - (12388141/741312)*n^3 + (87129737/1029600)*n^2 + (364945/2574)*n - 457 for n>3.
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EXAMPLE
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Some solutions for n=3
..0..0..0..0....0..0..0..1....0..0..0..0....0..0..1..1....2..1..0..0
..2..1..1..1....0..0..1..0....2..1..0..0....0..1..2..0....1..1..1..2
..1..2..2..0....1..1..1..0....1..1..2..0....1..2..1..0....1..1..2..2
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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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