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A303479
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Total volume of the family of rectangular prisms with dimensions p, q, and |q - p| where p divides q, n = p + q and p < q.
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0
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0, 0, 2, 6, 12, 36, 30, 90, 110, 168, 90, 560, 132, 396, 756, 930, 240, 1692, 306, 2436, 1876, 1140, 462, 6120, 2052, 1656, 3620, 5928, 756, 11304, 870, 8370, 6084, 2976, 8988, 22070, 1260, 3780, 9364, 26220, 1560, 27720, 1722, 18912, 29304, 5676, 2070
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OFFSET
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1,3
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LINKS
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FORMULA
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a(n) = Sum_{i=1..floor((n-1)/2} i * (n-i) * (n-2i) * (floor((n-i)/i) - floor((n-i-1)/i)).
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MATHEMATICA
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Table[Sum[i (n - i) (n - 2 i) (Floor[(n - i)/i] - Floor[(n - i - 1)/i]), {i, Floor[(n - 1)/2]}], {n, 50}]
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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