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A252818
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Number of n X 6 nonnegative integer arrays with upper left 0 and every value within 2 of its city block distance from the upper left and every value increasing by 0 or 1 with every step right or down.
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1
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16, 147, 1032, 5490, 23664, 86724, 279300, 809349, 2147638, 5289321, 12219498, 26705926, 55598468, 110890224, 212893984, 395014703, 710759820, 1243830839, 2122388828, 3538891338, 5777267504, 9249641452, 14545342212, 22495562705
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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) = (1/11404800)*n^12 + (1/211200)*n^11 + (37/345600)*n^10 + (143/103680)*n^9 + (27977/2419200)*n^8 + (83399/1209600)*n^7 + (319693/1036800)*n^6 + (34283/34560)*n^5 + (59941/28800)*n^4 + (482543/129600)*n^3 + (720359/277200)*n^2 + (44551/13860)*n + 3.
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EXAMPLE
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Some solutions for n=4
..0..1..2..3..4..5....0..1..2..3..4..5....0..1..2..3..3..4....0..1..2..2..3..4
..1..2..2..3..4..5....1..2..3..4..4..5....1..2..3..4..4..5....1..2..2..2..3..4
..2..3..3..3..4..5....2..2..3..4..5..5....1..2..3..4..5..5....2..3..3..3..4..5
..3..3..3..4..5..6....3..3..4..5..5..6....1..2..3..4..5..6....3..4..4..4..5..6
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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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