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%I #6 Apr 13 2017 04:05:53
%S 2,3,63,1249,4696,1200509
%N Numbers n such that the average of all proper divisors of all positive integers <= n is an integer.
%C Numbers n such that A002541(n)|A153485(n).
%C a(7) > 10^12. - _Giovanni Resta_, Apr 13 2017
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/RestrictedDivisorFunction.html">Restricted Divisor Function</a>
%H <a href="/index/Su#sums_of_divisors">Index entries for sequences related to sums of divisors</a>
%t Select[Range[2, 1300000], Mod[Sum[DivisorSigma[1, k] - k, {k, 1, #}], Sum[DivisorSigma[0, k] - 1, {k, 1, #}]] == 0 &]
%Y Cf. A000005, A000203, A001065, A002541, A003601, A023884, A023886, A027751, A153485, A226647, A284288.
%K nonn,more
%O 1,1
%A _Ilya Gutkovskiy_, Apr 02 2017
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