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Search: id:A076254
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| A076254 |
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A list of six integers with property that for every 3 numbers a,b,c from the list axbxc is an integer, where axb=a*b/(a+b) and axbxc=a*b*c/(a*b+a*c+b*c). This is the so-called replus operation. |
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+0
1
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| 248971642920, 497943285840, 746914928760, 995886571680, 1493829857520, 1991773143360
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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a(1) is the least common multiple of every ab+ac+bc, where a,b,c=1,2,3,4,6,8.
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REFERENCES
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Zoltan Kovacs, Abacus 2001.5 (Hungarian periodical)
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FORMULA
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a(n)=n*a(1) for n=1, 2, 3, 4 a(5)=6*a(1), a(6)=8*a(1)
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EXAMPLE
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a(1)*a(2)*a(3) = a(1)*2a(1)*3a(1)/(a(1)*2a(1) + a(1)*3a(1) + 2a(1)*3a(1)) = 6a(1)/11 is an integer because 11 | a(1).
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CROSSREFS
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Adjacent sequences: A076251 A076252 A076253 this_sequence A076255 A076256 A076257
Sequence in context: A108496 A112431 A132908 this_sequence A015432 A034618 A015418
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KEYWORD
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fini,full,nonn
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AUTHOR
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Miklos Kristof (kristmikl(AT)freemail.hu), Nov 05 2002
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