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Search: id:A108164
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| A108164 |
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Semiprimes p*q where both p and q are primes of the form 6n+1 (A002476). |
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+0
5
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| 49, 91, 133, 169, 217, 247, 259, 301, 361, 403, 427, 469, 481, 511, 553, 559, 589, 679, 703, 721, 763, 793, 817, 871, 889, 949, 961, 973, 1027, 1057, 1099, 1141, 1147, 1159, 1261, 1267, 1273, 1333, 1339, 1351, 1369, 1387, 1393, 1417, 1477, 1501, 1561, 1591
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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These are the products of terms from A107890 excluding multiples of 3.
Every semiprime not divisible by 2 or 3 must be in one of these three disjoint sets:
A108164 = the product of two primes of the form 6n+1 (A002476),
A108166 = the product of two primes of the form 6n-1 (A007528),
A108172 = the product of a prime of the form 6n+1 and a prime of the form 6n-1.
The product of two primes of the form 6n+1 is a semiprime of the form 6n+1.
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REFERENCES
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M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 870.
K. G. Reuschle, Tafeln Complexer Primzahlen. K\"{o}nigl. Akademie der Wissenschaften, Berlin, 1875, p. 1.
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LINKS
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M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, December 1972 [alternative scanned copy].
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FORMULA
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{a(n)} = {p*q where both p and q are in A002476}.
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CROSSREFS
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Cf. A001358, A002476, A107890.
Adjacent sequences: A108161 A108162 A108163 this_sequence A108165 A108166 A108167
Sequence in context: A093894 A090825 A118886 this_sequence A020158 A084632 A020176
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KEYWORD
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easy,nonn
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AUTHOR
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Jonathan Vos Post (jvospost2(AT)yahoo.com), Jun 13 2005
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EXTENSIONS
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Edited and extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Oct 15 2005
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