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Search: id:A008339
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| A008339 |
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a(1)=1; for n >= 1, a(n+1) = lcm(a(n),n) / gcd(a(n),n). |
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+0
3
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| 1, 1, 2, 6, 6, 30, 5, 35, 280, 2520, 252, 2772, 231, 3003, 858, 1430, 5720, 97240, 437580, 8314020, 415701, 969969, 176358, 4056234, 2704156, 67603900, 2600150, 70204050, 10029150, 290845350, 9694845, 300540195, 9617286240, 35263382880, 1037158320
(list; graph; listen)
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OFFSET
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1,3
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COMMENT
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a(n+1) = Product(A098666(n,k): 1<=k<=n), row-products of triangle A098666. - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Sep 20 2004
a(n+1) is divisible by all primes in (n/2, n]; thus lim_{n->infinity} a(n) = infinity. - Franklin T. Adams-Watters (FrankTAW(AT)Netscape.net), Dec 13 2006
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FORMULA
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a(1) = 1, a(n) = a(n-1)*r/s where y is the largest divisor of a(n-1) with r*s = n. - Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Jul 01 2003
a(1) = 1, a(n+1) = a(n)*n/gcd(a(n),n)^2. - Franklin T. Adams-Watters (FrankTAW(AT)Netscape.net), Dec 13 2006
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MAPLE
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A008339 := proc(n) option remember; if n = 1 then 1 else lcm(A008339(n-1), n-1)/gcd(A008339(n-1), n-1); fi; end;
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MATHEMATICA
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FoldList[ LCM[ #1, #2 ]/GCD[ #1, #2 ]&, 1, Range[ 30 ] ]
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CROSSREFS
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Sequence in context: A085087 A072983 A055204 this_sequence A077139 A068629 A144361
Adjacent sequences: A008336 A008337 A008338 this_sequence A008340 A008341 A008342
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
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Mathematica Program Aug 15 1997 (Olivier Gerard).
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