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A206367
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(2,3)-imperfect numbers.
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1
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3, 15, 18, 36, 72, 255, 1152, 2709, 65535, 294912, 4294967295, 4380480000
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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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MATHEMATICA
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f[p_, e_] := ((-1)^e + p^(e + 1))/(p + 1); s[n_] := Times @@ f @@@ FactorInteger[n]; s[1] = 1; Select[Range[300000], # == 3 * s[s[#]] &] (* Amiram Eldar, Sep 12 2023 *)
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PROG
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(PARI) beta(n) = sumdiv(n, d, d*(-1)^bigomega(n/d));
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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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