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A077110
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Nearest integer cube to n^2.
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8
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0, 1, 1, 8, 8, 27, 27, 64, 64, 64, 125, 125, 125, 125, 216, 216, 216, 343, 343, 343, 343, 512, 512, 512, 512, 729, 729, 729, 729, 729, 1000, 1000, 1000, 1000, 1000, 1331, 1331, 1331, 1331, 1331, 1728, 1728, 1728, 1728, 1728, 2197, 2197, 2197
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OFFSET
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0,4
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LINKS
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FORMULA
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EXAMPLE
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a(10)=125, as 125=5^3 is the nearest cube to 100=10^2.
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MATHEMATICA
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nic[n_]:=Module[{n2=n^2, s3, c1, c2}, s3=Surd[n2, 3]; c1=Floor[s3]^3; c2= Ceiling[ s3]^3; If[n2-c1<c2-n2, c1, c2]]; Array[nic, 50, 0] (* Harvey P. Dale, Jul 05 2015 *)
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PROG
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(Python)
from sympy import integer_nthroot
n2 = n**2
a = integer_nthroot(n2, 3)[0]
a2, a3 = a**3, (a+1)**3
return a3 if a3+a2-2*n2 < 0 else a2 # Chai Wah Wu, Sep 24 2021
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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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