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A331203
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Numbers k such that k/(digsum(k)) is an integer cube.
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0
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1, 2, 3, 4, 5, 6, 7, 8, 9, 72, 243, 320, 486, 512, 640, 704, 832, 960, 1000, 1088, 1125, 2000, 2401, 3000, 3430, 4000, 4116, 4802, 5000, 5145, 5831, 6000, 6174, 6517, 6860, 7000, 7546, 8000, 8575, 8918, 9000, 9216, 9947, 19683, 35152, 35937, 41743, 43940, 46137
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OFFSET
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1,2
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COMMENTS
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If m belongs to the sequence, then 1000*m also belongs to the sequence. - Rémy Sigrist, Jan 12 2020
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LINKS
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EXAMPLE
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a(11) = 243: 243/(2 + 4 + 3) = 27 = 3^3.
a(12) = 320: 320/(3 + 2 + 0) = 64 = 4^3.
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MATHEMATICA
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Select[Range[100000], IntegerQ[CubeRoot[#/Total[IntegerDigits[#]]]] &]
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PROG
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(Magma) [n : n in[1 .. 1000] | IsIntegral((n/(&+Intseq(n)))^(1/3))];
(PARI) is(n) = my (k=n/sumdigits(n)); type(k)==type(42) && ispower(k, 3) \\ Rémy Sigrist, Jan 12 2020
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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