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A192703
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Number of 4X2 integer matrices with each row summing to zero, row elements in nondecreasing order, rows in lexicographically nondecreasing order, and the sum of squares of the elements <= 2*n^2 (number of collections of 4 zero-sum 2-vectors with total modulus squared not more than 2*n^2, ignoring vector and component permutations)
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1
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2, 6, 12, 23, 41, 70, 106, 159, 230, 323, 436, 578, 757, 975, 1232, 1536, 1889, 2317, 2797, 3355, 3994, 4711, 5523, 6438, 7465, 8618, 9888, 11296, 12839, 14557, 16398, 18449, 20689, 23115, 25758, 28591, 31673, 34995, 38586, 42415, 46528, 50984, 55687
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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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EXAMPLE
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Some solutions for 4X2 <= 2*4^2
.-3..3...-3..3...-1..1...-2..2...-3..3...-2..2...-2..2...-1..1...-1..1...-2..2
..0..0...-1..1...-1..1...-2..2...-2..2...-2..2....0..0...-1..1...-1..1...-2..2
..0..0...-1..1....0..0....0..0...-1..1...-2..2....0..0...-1..1...-1..1...-2..2
..0..0....0..0....0..0....0..0....0..0...-1..1....0..0...-1..1....0..0...-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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