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A110379
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a(n) = Sum_{composite c <= n} n!/c!.
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0
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1, 5, 31, 217, 1737, 15634, 156341, 1719751, 20637013, 268281169, 3755936367, 56339045506, 901424728097, 15324220377649, 275835966797683, 5240883369155977, 104817667383119541, 2201171015045510362
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OFFSET
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4,2
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LINKS
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EXAMPLE
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a(6) = 6!(1/4! + 1/6!) = 31.
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MAPLE
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a:=proc(n) local s, i :s:=0: for i from 4 to n do if isprime(i)=false then s:=s+1/i! else s:=s: fi od: n!*s; end; seq(a(n), n=4..24); # Emeric Deutsch, Jul 25 2005
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CROSSREFS
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KEYWORD
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easy,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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