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A067075
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a(n) is the smallest number m such that the sum of the digits of m^3 is equal to n^3.
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9
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OFFSET
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0,3
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COMMENTS
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a(n) >= ceiling(A051885(n^3)^(1/3)). For example a(7) >= ceiling(A051885(7^3)^(1/3)) = ceiling((2*10^38-1)^(1/3)) = 5848035476426 - David A. Corneth, Aug 23 2018
a(8) <= 99995999799995999999999.
a(9) <= 999699989999999949999999999999999.
a(10) <= 199999999929999999999949999999999999999999999.
(End)
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LINKS
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EXAMPLE
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a(3) = 27 as 27^3 = 19683 is the smallest cube whose digit sum = 27 = 3^3.
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MATHEMATICA
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Do[k = 1; While[Plus @@ IntegerDigits[k^3] != n^3, k++ ]; Print[k], {n, 1, 6}] (* Ryan Propper, Jul 07 2005 *)
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PROG
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(PARI) a(n) = my(k=0); while (sumdigits(k^3) != n^3, k++); k; \\ Seiichi Manyama, Aug 12 2017
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CROSSREFS
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KEYWORD
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nonn,base,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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