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A069624
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Number of different values taken by the integer part of n^(1/k) for all k > 1.
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2
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1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5
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OFFSET
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1,4
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LINKS
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EXAMPLE
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a(28) = 4: floor(28^(1/2)) = 5, floor(28^(1/3)) = 3, floor(28^(1/4)) = 2, floor (28^(1/5)) = 1 = floor(28^(1/k), (k > 5)), etc. The distinct values are 1,2,3 and 5.
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MAPLE
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local s, k, a ;
s := {} ;
for k from 2 do
a := floor(n^(1/k)) ;
s := s union {a} ;
if a = 1 then
break;
end if;
end do:
nops(s) ;
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MATHEMATICA
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f[n_] := Block[{k = 1}, While[ Floor[n^(1/k)] != 1, k++ ]; k]; Table[ Length[ Union[ Table[ Floor[n^(1/k)], {k, 2, f[n]+1}]]], {n, 1, 105}]
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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