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A073046
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Write 2*n=p+q (p,q prime), p*q minimal; then a(n)=p*q.
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4
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4, 9, 15, 21, 35, 33, 39, 65, 51, 57, 95, 69, 115, 161, 87, 93, 155, 217, 111, 185, 123, 129, 215, 141, 235, 329, 159, 265, 371, 177, 183, 305, 427, 201, 335, 213, 219, 365, 511, 237, 395, 249, 415, 581, 267, 445, 623, 1501, 291, 485, 303, 309, 515, 321, 327
(list; graph; refs; listen; history; internal format)
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OFFSET
| 2,1
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COMMENTS
| Least semiprime whose sum of prime factors equals 2*n.
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LINKS
| Reinhard Zumkeller, Table of n, a(n) for n = 2..10000
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EXAMPLE
| n=13: 2n=26; 26=23+3=19+7=13+13; 23*3=minimal => p*q=23*3=69
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PROG
| (Haskell)
a073046 n = head $ dropWhile (== 0) $
zipWith (*) prims $ map (a061397 . (2*n -)) prims
where prims = takeWhile (<= n) a000040_list
-- Reinhard Zumkeller, Aug 28 2011
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CROSSREFS
| Cf. A000040, A061397.
Cf. A102084, A193315.
Sequence in context: A103395 A103393 A103392 * A066495 A134227 A055999
Adjacent sequences: A073043 A073044 A073045 * A073047 A073048 A073049
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KEYWORD
| nonn
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AUTHOR
| Werner Sand (werner.sand(AT)tiscalimail.de), Aug 31 2002
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EXTENSIONS
| Corrected by Ray Chandler (rayjchandler(AT)sbcglobal.net), Jun 11 2005
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