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%I A243473 #15 May 08 2016 22:42:25
%S A243473 0,1,1,3,1,1,1,7,4,4,1,4,1,5,3,15,1,7,1,11,11,7,1,3,6,8,13,1,1,7,1,31,
%T A243473 5,10,13,55,1,11,17,5,1,9,1,10,11,13,1,19,8,43,7,23,1,11,17,8,23,16,1,
%U A243473 9,1,17,41,63,19,13,1,29,9,37,1,41,1,20,49,16
%N A243473 a(n) = numerator(sigma(n)/n) - denominator(sigma(n)/n) where sigma(n) = sum of divisors of n.
%C A243473 a(n) = 1 for n prime or perfect (A053813).
%C A243473 a(n) = A001065(n) when n is in A014567.
%C A243473 a(n) > n for n in A069057. - _Michel Marcus_, May 04 2016
%H A243473 Michel Marcus, <a href="/A243473/b243473.txt">Table of n, a(n) for n = 1..10000</a>
%F A243473 a(n) = A017665(n) - A017666(n).
%t A243473 f[n_] := DivisorSigma[1, n]/n; Table[Numerator[f@ n] - Denominator[f@ n], {n, 76}] (* _Michael De Vlieger_, Sep 09 2015 *)
%o A243473 (PARI) a(n) = numerator(ab = sigma(n)/n) - denominator(ab);
%Y A243473 Cf. A000203, A001065, A014567, A017665, A017666, A053813, A069057.
%K A243473 nonn
%O A243473 1,4
%A A243473 _Michel Marcus_, Jun 05 2014

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