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A330872
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Numbers k such that k and k+1 are both primitive abundant numbers (A071395).
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6
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82004, 158235, 516704, 2921535, 5801984, 10846016, 12374144, 12603824, 18738224, 24252074, 32409530, 33696975, 35356544, 36149295, 41078114, 42541190, 43485584, 65090864, 88304475, 90725775, 181480695, 183872535, 213261795, 233762528, 242301344, 254502495, 254630144
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OFFSET
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1,1
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COMMENTS
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Not to be confused with A283418 in which the primitive abundant numbers can have perfect numbers as divisors (as defined in A091191).
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LINKS
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EXAMPLE
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82004 is a term since both 82004 and 82005 are abundant, and all of their proper divisors are deficient numbers.
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MATHEMATICA
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primAbQ[n_] := DivisorSigma[1, n] > 2 n && AllTrue[Most @ Rest @ Divisors[n], DivisorSigma[1, #] < 2*# &]; q1 = False; seq = {}; Do[q2 = primAbQ[n]; If[q1 && q2, AppendTo[seq, n - 1]]; q1 = q2, {n, 2, 6*10^6}]; seq
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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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