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A369007
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Numbers k for which k' / gcd(k,k') is a multiple of 27, where k' stands for the arithmetic derivative of k, A003415(k).
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4
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1, 158, 160, 208, 212, 275, 329, 374, 410, 428, 473, 482, 515, 533, 629, 698, 700, 707, 713, 785, 910, 914, 952, 1055, 1058, 1067, 1072, 1076, 1078, 1080, 1183, 1204, 1238, 1346, 1404, 1431, 1445, 1454, 1490, 1562, 1661, 1691, 1724, 1813, 1841, 1865, 1888, 1937, 1994, 2102, 2219, 2291, 2320, 2372, 2426, 2432, 2570
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OFFSET
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1,2
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COMMENTS
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Question: What is the asymptotic density of these terms? 0.0253...?
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LINKS
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PROG
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(PARI)
A083345(n) = { my(f=factor(n)); numerator(vecsum(vector(#f~, i, f[i, 2]/f[i, 1]))); };
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CROSSREFS
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Positions of multiples of 27 in A083345.
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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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