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A091454
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Integers k such that 3*phi(k) < k.
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3
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30, 42, 60, 66, 78, 84, 90, 102, 114, 120, 126, 132, 138, 150, 156, 168, 174, 180, 186, 198, 204, 210, 222, 228, 234, 240, 246, 252, 258, 264, 270, 276, 282, 294, 300, 306, 312, 318, 330, 336, 342, 348, 354, 360, 366, 372, 378, 390, 396, 402, 408, 414, 420
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OFFSET
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1,1
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COMMENTS
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If k is present so are all m*k, m>1.
The smallest odd number in this sequence is 111546435 = 3*5*7*11*...*23. - T. D. Noe, Jan 15 2004
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LINKS
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MAPLE
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filter:= n -> 3*numtheory:-phi(n) < n:
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MATHEMATICA
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Select[ Range[437], 3EulerPhi[ # ] < # & ]
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PROG
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(PARI) is(n) = 3*eulerphi(n) < n; \\ Amiram Eldar, Apr 07 2024
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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