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Search: id:A070826
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| 1, 3, 15, 105, 1155, 15015, 255255, 4849845, 111546435, 3234846615, 100280245065, 3710369067405, 152125131763605, 6541380665835015, 307444891294245705, 16294579238595022365, 961380175077106319535
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Identical with A002110(n)/2, n>=1.
a(n+1) is the least odd number with exactly n distinct prime divisors. - Labos E. (labos(AT)ana.sote.hu), Mar 24 2003
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FORMULA
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a(n)=product(p(n), n=1..n) with p(n) := A000040(n).
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MAPLE
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with (numtheory):a:=n->mul(ithprime(j), j=2..n):seq(a(n), n=1..17); [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Aug 24 2008]
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MATHEMATICA
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Rest[ FoldList[ Times, 1, Prime[ Range[ 18]] ]]/2 (from Robert G. Wilson v Feb 17 2004)
FoldList[Times, 1, Prime[Range[2, 18]]] [From Zak Seidov (zakseidov(AT)yahoo.com), Jan 26 2009]
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CROSSREFS
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Cf. A003266 (for Fibonacci), A070825 (for Lucas), A003046 (for Catalan).
Cf. also A091852.
Sequence in context: A001147 A000268 A118750 this_sequence A048599 A129731 A088109
Adjacent sequences: A070823 A070824 A070825 this_sequence A070827 A070828 A070829
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KEYWORD
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nonn,easy
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AUTHOR
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Wolfdieter Lang (wolfdieter.lang(AT)physik.uni-karlsruhe.de), May 10, 2002
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