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A063919
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Sum of proper unitary divisors (or unitary aliquot parts) of n (including 1).
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23
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1, 1, 1, 1, 1, 6, 1, 1, 1, 8, 1, 8, 1, 10, 9, 1, 1, 12, 1, 10, 11, 14, 1, 12, 1, 16, 1, 12, 1, 42, 1, 1, 15, 20, 13, 14, 1, 22, 17, 14, 1, 54, 1, 16, 15, 26, 1, 20, 1, 28, 21, 18, 1, 30, 17, 16, 23, 32, 1, 60, 1, 34, 17, 1, 19, 78, 1, 22, 27, 74, 1, 18, 1, 40, 29, 24, 19, 90, 1, 22, 1, 44
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,6
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COMMENTS
| For definition of unitary divisor see A034448.
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LINKS
| Harry J. Smith, Table of n, a(n) for n=1,...,1000
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FORMULA
| a(n)=A034460(n), n>1. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 02 2008]
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EXAMPLE
| a(10)=8 because the unitary divisors of 10 are 1, 2, 5 and 10, with sum 18 and 18-10 = 8.
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MATHEMATICA
| a[n_] := Total[Select[Divisors[n], GCD[#, n/#] == 1&]]-n; a[1] = 1; Table[a[n], {n, 82}] (* From Jean-François Alcover, Aug 31 2011 *)
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PROG
| (PARI) usigma(n) = sumdiv(n, d, if(gcd(d, n/d)==1, d)) { for (n=1, 1000, if (n>1, a=usigma(n) - n, a=1); write("b063919.txt", n, " ", a) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Sep 02 2009]
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CROSSREFS
| The values of sequence are A034448(n)-n (for n > 1).
Cf. A001065, A034448.
Sequence in context: A126795 A064793 A034460 * A072815 A080304 A166142
Adjacent sequences: A063916 A063917 A063918 * A063920 A063921 A063922
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KEYWORD
| easy,nonn,nice
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AUTHOR
| Felice Russo (frusso(AT)micron.com), Aug 31 2001
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