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A302125
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Numbers whose deficiency is a perfect number.
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0
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7, 15, 29, 52, 62, 182, 230, 315, 344, 592, 944, 998, 1155, 2012, 2570, 4028, 6710, 15128, 19688, 20264, 30248, 36224, 38252, 40730, 43964, 52088, 90332, 96128, 168116, 195224, 258512, 262112, 451952, 538112, 991904, 1209632, 1237856, 1659128, 2080544, 2085710, 2102272, 2186132
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OFFSET
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1,1
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COMMENTS
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Subsequence of deficient numbers (A005100) whose deficiency (A033879) is a member of perfect numbers (A000396).
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LINKS
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EXAMPLE
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52 is in the sequence since the divisors of 52 are {1, 2, 4, 13, 26 & 52} so d(52) = 98 and 2*52 - 98 = 6, a perfect number.
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MATHEMATICA
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fQ[n_] := PerfectNumberQ[2n - DivisorSigma[1, n]]; Select[ Range@ 2500000, fQ]
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PROG
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(PARI) for(n=1, 25*10^5, d=2*n-sigma(n); d>0&&sigma(d)==2*d&&print1(n ", "))
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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