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A165453
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Linear interpolation of the sequence that maps an entry of A002378 to the corresponding entry of A006331.
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0
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0, 1, 2, 4, 6, 8, 10, 13, 16, 19, 22, 25, 28, 32, 36, 40, 44, 48, 52, 56, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 116, 122, 128, 134, 140, 146, 152, 158, 164, 170, 176, 182, 189, 196, 203, 210, 217, 224, 231, 238, 245, 252, 259, 266, 273, 280, 288, 296, 304
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OFFSET
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0,3
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LINKS
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FORMULA
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a(0)=0, a(n) = max(min(a(n-1)+x, n+a(n-x))), where the maximum is taken over all values for x from 1 to n.
a(n) = (1/3)*t*(3*n + 1 - t^2), where t = floor(sqrt(n)+1/2). - Ridouane Oudra, Feb 22 2021
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MATHEMATICA
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Table[Sum[Floor[Sqrt[n + 1 - k] + 1/2], {k, n + 1}], {n, 0, 100}] (* Wesley Ivan Hurt, Dec 01 2020 *)
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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Friedrich Regen (friedrich.regen(AT)tu-ilmenau.de), Sep 20 2009
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STATUS
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approved
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