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Search: id:A133582
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| A133582 |
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a(n) is found from a(n-1) by dividing by D-1 and multiplying by D, where D is the smallest number that is not a divisor of a(n-1). |
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+0
1
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| 1, 2, 3, 6, 8, 12, 15, 30, 40, 60, 70, 105, 210, 280, 420, 480, 560, 840, 945, 1890, 2520, 2772, 3465, 6930, 9240, 10395, 20790, 27720, 30030, 40040, 60060, 68640, 80080, 120120, 135135, 270270, 360360, 384384, 480480, 540540, 617760, 720720, 765765
(list; graph; listen)
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OFFSET
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1,2
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EXAMPLE
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Smallest number not a factor of 30 is 4, so next term after 30 is (30/3)*4 = 40.
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MAPLE
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A133582 := proc(n) option remember ; local d ; if n = 1 then 1; else for d from 2 do if A133582(n-1) mod d <> 0 then RETURN( A133582(n-1)*d/(d-1) ) ; fi ; od; fi ; end: seq(A133582(n), n=1..40) ; - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jan 07 2008
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MATHEMATICA
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a = {1, 2}; Do[i = 1; While[IntegerQ[a[[ -1]]/i], i++ ]; AppendTo[a, (i/(i - 1))*a[[ -1]]], {50}]; a - Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Dec 29 2007
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CROSSREFS
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Sequence in context: A035106 A122378 A111242 this_sequence A085642 A049194 A058298
Adjacent sequences: A133579 A133580 A133581 this_sequence A133583 A133584 A133585
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KEYWORD
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nonn
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AUTHOR
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J. Lowell, jhbubby(AT)mindspring.com, Dec 26 2007
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EXTENSIONS
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More terms from Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Dec 29 2007
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