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A294664
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Numbers n such that the largest digit of n^3 is 4.
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6
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7, 68, 70, 324, 680, 700, 3240, 6800, 7000, 7618, 31177, 32400, 52308, 68000, 69314, 70000, 76180, 311770, 324000, 353068, 523080, 680000, 693140, 700000, 756658, 761800, 1039247, 2715974, 2732441, 3117700, 3240000, 3511617, 3530680, 4689368, 5230800, 6800000, 6931400, 7000000
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OFFSET
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1,1
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COMMENTS
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For any term a(n), all numbers of the form a(n)*10^k, k >= 0, are in this sequence. Primitive terms, i.e., not of this form (or equivalently: without trailing '0'), are 7, 68, 324, 7618, 31177, 52308, 69314, 353068, 756658, 1039247, 2715974, 2732441, 3511617, 4689368, 7571814, 12811968, 15904541, ...
All terms have last nonzero digit 1, 4, 7 or 8 and leading digit <= 7. - Robert Israel, Nov 13 2017
The number formed by the first m digits of a term is always less than c*10^m with c = (4/9)^(1/3) = .7631428283688879... - M. F. Hasler, Nov 13 2017
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LINKS
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EXAMPLE
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7 is in the sequence because the largest digit of 7^3 = 343 is 4.
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MAPLE
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select(n -> max(convert(n^3, base, 10))=4, [$1..10^6]); # Robert Israel, Nov 13 2017
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PROG
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(PARI) for(n=1, 2e8, vecmax(digits(n^3))==4&&print1(n", "))
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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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