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A337800
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Numbers of the form (2^i)*(3^j) or (2^i)*(5^j).
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4
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1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 16, 18, 20, 24, 25, 27, 32, 36, 40, 48, 50, 54, 64, 72, 80, 81, 96, 100, 108, 125, 128, 144, 160, 162, 192, 200, 216, 243, 250, 256, 288, 320, 324, 384, 400, 432, 486, 500, 512, 576, 625, 640, 648, 729, 768, 800, 864, 972, 1000
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OFFSET
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1,2
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COMMENTS
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Union of A003586 and A003592.
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LINKS
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Vaclav Kotesovec, Table of n, a(n) for n = 1..10000
Vaclav Kotesovec, Graph - the asymptotic ratio (64000000 terms)
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FORMULA
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a(n) ~ exp(sqrt(2*log(2)*log(3)*log(5)*n / log(15))) / sqrt(2).
Sum_{n>=1} 1/a(n) = 7/2. - Amiram Eldar, Sep 23 2020
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MATHEMATICA
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n = 10^4; Join[Table[2^i*3^j, {i, 0, Log[2, n]}, {j, 0, Log[3, n/2^i]}], Table[2^i*5^j, {i, 0, Log[2, n]}, {j, 0, Log[5, n/2^i]}]] // Flatten // Union (* Amiram Eldar, Sep 23 2020 *)
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CROSSREFS
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Cf. A003586, A003592, A257997, A258023, A337801.
Sequence in context: A048645 A173786 A093863 * A091902 A067698 A110495
Adjacent sequences: A337797 A337798 A337799 * A337801 A337802 A337803
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KEYWORD
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nonn,easy
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AUTHOR
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Vaclav Kotesovec, Sep 22 2020
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STATUS
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approved
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