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A295220
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a(n) = Sum_{i=1..floor(n/2)} floor((n+i)/i) - floor((n-i-1)/i).
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1
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0, 3, 3, 6, 5, 9, 7, 11, 10, 13, 11, 17, 13, 17, 17, 20, 17, 23, 19, 25, 23, 25, 23, 31, 26, 29, 29, 33, 29, 37, 31, 37, 35, 37, 37, 44, 37, 41, 41, 47, 41, 49, 43, 49, 49, 49, 47, 57, 50, 55, 53, 57, 53, 61, 57, 63, 59, 61, 59, 71, 61, 65, 67, 70, 67, 73
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OFFSET
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1,2
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COMMENTS
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It appears that the odd prime numbers are fixed points of the sequence.
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LINKS
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MAPLE
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MATHEMATICA
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Table[Sum[Floor[(n + i)/i] - Floor[(n - i - 1)/i], {i, Floor[n/2]}], {n, 60}]
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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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