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A033879
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Deficiency of n, or 2n - (sum of divisors of n).
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15
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1, 1, 2, 1, 4, 0, 6, 1, 5, 2, 10, -4, 12, 4, 6, 1, 16, -3, 18, -2, 10, 8, 22, -12, 19, 10, 14, 0, 28, -12, 30, 1, 18, 14, 22, -19, 36, 16, 22, -10, 40, -12, 42, 4, 12, 20, 46, -28, 41, 7, 30, 6, 52, -12, 38, -8, 34, 26, 58, -48, 60, 28, 22, 1, 46, -12, 66, 10, 42, -4, 70, -51
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,3
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COMMENTS
| Records for the sequence of the absolute values are in A075728 and the indices of these records in A074918. - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Mar 02 2007
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REFERENCES
| R. K. Guy, Unsolved Problems in Number Theory, Section B2.
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LINKS
| T. D. Noe, Table of n, a(n) for n=1..2000
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FORMULA
| a(n) = A005843(n)-A000203(n). [From Omar E. Pol (info(AT)polprimos.com), Dec 14 2008]
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MAPLE
| with(numtheory); n->2*n-sigma(n);
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MATHEMATICA
| Table[2n-DivisorSigma[1, n], {n, 80}] (* From Harvey P. Dale, Oct 24 2011 *)
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CROSSREFS
| Cf. A005101. Equals -A033880.
Cf. A074918, A075728.
Cf. A000203, A005843. [From Omar E. Pol (info(AT)polprimos.com), Dec 14 2008]
Cf. A192895.
Sequence in context: A103977 A109883 A033880 * A033883 A106316 A126707
Adjacent sequences: A033876 A033877 A033878 * A033880 A033881 A033882
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KEYWORD
| sign,nice
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
| Definition corrected Jul 04 2005
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