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Search: id:A134339
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| A134339 |
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a(n) = product of the positive "non-isolated divisors" of (2n). A divisor, k, of n is non-isolated if (k-1) or (k+1) also divides n. |
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+0
2
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| 2, 2, 6, 2, 2, 24, 2, 2, 6, 40, 2, 24, 2, 2, 180, 2, 2, 24, 2, 40, 252, 2, 2, 24, 2, 2, 6, 112, 2, 720, 2, 2, 6, 2, 2, 1728, 2, 2, 6, 40, 2, 1008, 2, 2, 16200, 2, 2, 24, 2, 40, 6, 2, 2, 24, 220, 112, 6, 2, 2, 720, 2, 2, 252, 2, 2, 3168, 2, 2, 6, 40, 2, 1728, 2, 2, 180, 2, 2, 3744, 2, 40, 6
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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No odd integer has any non-isolated divisors.
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LINKS
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Leroy Quet, Home Page (listed in lieu of email address)
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FORMULA
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a(n) = A007955(2n) / A134338(2n). - Chandler
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EXAMPLE
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The divisors of 2*10 = 20 are 1,2,4,5,10,20. Of these, 1,2,4,5 are the non-isolated divisors. So a(10) = 1*2*4*5 = 40.
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CROSSREFS
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Cf. A134338.
Sequence in context: A077198 A046110 A126889 this_sequence A162299 A110141 A129750
Adjacent sequences: A134336 A134337 A134338 this_sequence A134340 A134341 A134342
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KEYWORD
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nonn
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AUTHOR
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Leroy Quet Oct 21 2007
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EXTENSIONS
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Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Jun 24 2008
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