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Search: id:A108219
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| A108219 |
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Numbers n such that A001414(n) is a golden semiprime, where A001414 is the sum of primes dividing n (with repetition). |
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| 8, 9, 26, 44, 105, 112, 125, 126, 150, 160, 180, 192, 216, 243, 292, 568, 639, 1174, 1407, 1448, 1629, 1675, 2010, 2144, 2379, 2412, 2685, 2722, 2864, 3222, 3355, 3835, 3999, 4026, 4107, 4543, 4602, 5035, 5709, 5978, 6042, 6235, 6307, 6355, 6490, 7482
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OFFSET
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1,1
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COMMENT
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Numbers n such that A001414(n) and A001414(n+1) are both golden semiprimes: 8, 125, 153759, 247455, 678807, 1243499, 1243500, Notice that the last two terms indicate a triple. Conjecture: this subsequence is infinite.
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EXAMPLE
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5709 = 3*11*173 is in the sequence because 3+11+173 = 187 = 11*17, and
11*phi-17 = 0.79837... < 1.
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CROSSREFS
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Cf. A001414, A108540.
Sequence in context: A114130 A130100 A041134 this_sequence A041317 A042311 A003997
Adjacent sequences: A108216 A108217 A108218 this_sequence A108220 A108221 A108222
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KEYWORD
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nonn
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AUTHOR
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Jason Earls (zevi_35711(AT)yahoo.com), Jun 16 2005
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