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Search: id:A135937
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| A135937 |
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a(1)=1. For n>=2, a(n) = product{d|a(n-1)} (d+1), where the product is over all positive divisors d of a(n-1). |
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2
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OFFSET
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1,2
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COMMENT
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The next term is a lot bigger than 70000! and is too large to include. - Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Dec 31 2007
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EXAMPLE
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The positive divisors of a(3)=6 are 1,2,3,6. So a(4) = (1+1)*(2+1)*(3+1)*(6+1) = 2*3*4*7 = 168.
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MATHEMATICA
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a = {1}; Do[AppendTo[a, Times @@ (Divisors[a[[ -1]]] + 1)], {4}]; a - Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Dec 31 2007
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CROSSREFS
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Cf. A135938.
Sequence in context: A088430 A051240 A003189 this_sequence A137532 A072116 A055696
Adjacent sequences: A135934 A135935 A135936 this_sequence A135938 A135939 A135940
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KEYWORD
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nonn
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AUTHOR
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Leroy Quet (qq-quet(AT)mindspring.com), Dec 07 2007
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EXTENSIONS
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a(5) from Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Dec 31 2007
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