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Search: id:A103654
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| A103654 |
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Primes which are the average of two successive semiprimes. |
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+0
4
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| 5, 53, 67, 89, 113, 131, 173, 211, 251, 293, 307, 337, 379, 409, 449, 487, 491, 499, 631, 683, 701, 727, 751, 769, 787, 919, 941, 953, 991, 1009, 1039, 1051, 1063, 1117, 1193, 1259, 1399, 1459, 1471, 1499, 1511, 1567, 1627, 1697, 1709, 1733, 1759, 1787, 1801
(list; graph; listen)
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OFFSET
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1,1
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FORMULA
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p=(q+r)/2, where q<p and r>p are two successive semiprimes closest to p.
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EXAMPLE
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a(3)=67 because 65 and 69 are two successive semiprimes closest to 67, and 67=(65+69)/2;a(333)=22679 because 22677 and 22691 are two successive semiprimes closest to 22679, and 22679=(22677+22681)/2.
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CROSSREFS
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Indices of these primes: A103655. Primes: A000040, semiprimes: A001358, number of primes between successive semiprimes: A088700, number of semiprimes between two successive primes: A103668.
Cf. A000040, A088700, A103655, A001358, A103668, A103669.
Adjacent sequences: A103651 A103652 A103653 this_sequence A103655 A103656 A103657
Sequence in context: A107803 A088712 A090153 this_sequence A079385 A091272 A142399
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KEYWORD
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nonn
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AUTHOR
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Zak Seidov (zakseidov(AT)yahoo.com), Feb 12 2005
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