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A231547
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Numbers n such that n < sigma(n) - sigma(n-1).
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2
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12, 18, 20, 24, 30, 36, 42, 48, 54, 60, 72, 80, 84, 90, 96, 102, 104, 108, 114, 120, 126, 132, 138, 140, 144, 150, 156, 160, 162, 168, 174, 180, 192, 198, 200, 204, 210, 216, 224, 228, 234, 240, 252, 258, 260, 264, 270, 272, 276, 280, 282, 288, 294, 300, 306
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OFFSET
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1,1
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COMMENTS
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Also numbers n such that antisigma(n) < antisigma(n-1), where antisigma(n) = A024816(n) = the sum of the non-divisors of n that are between 1 and n.
Numbers n such that A163553(n-1) < 0.
Numbers n such that antisigma(n) > antisigma(n-1) = A231711.
Numbers n such that antisigma(n) = antisigma(n-1) = A231545.
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LINKS
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EXAMPLE
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12 is in sequence because antisigma(12) = 50 < antisigma(11) = 54.
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MATHEMATICA
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Select[Range[350], #<(DivisorSigma[1, #]-DivisorSigma[1, #-1])&] (* Harvey P. Dale, May 26 2016 *)
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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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