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A230164
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Numbers n such that n' = sigma(n), where n' is the arithmetic derivative of n.
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5
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OFFSET
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1,1
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COMMENTS
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LINKS
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EXAMPLE
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If n=17296 then n’=sigma(n)= 35712. If n=24016 then n’=sigma(n)= 49600.
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MAPLE
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with(numtheory); P:= proc(q) local a, n, p;
for n from 1 to q do a:=n*add(op(2, p)/op(1, p), p=ifactors(n)[2]);
if sigma(n)=a then print(n); fi; od; end: P(10^9);
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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