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A085865
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a(1) = 2, a(n+1) = a(n)*{sigma(a(n))}, where sigma(n) is the sum of the divisors function.
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1
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2, 6, 72, 14040, 707616000, 2299654269739008000, 25353370781704805143366427867873280000, 3361021040447648920437074194752848938805829494939344230020451929790873600000
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OFFSET
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1,1
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COMMENTS
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a(1) = 1, a(n+1) = a(n) + sigma(a(n)) gives A081973.
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LINKS
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EXAMPLE
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a(3) = 72 and sigma(72)= 195, hence a(4) = 72*195 = 14040.
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PROG
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(PARI) for(n=1, 9, if(n==1, a=2, a*=sigma(a)); print(a); )
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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