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%I #21 Jul 08 2020 21:36:26
%S 1,3,40,84,124,318,496,672,732,790,1320,1488,3154,4464,5271,8128,9156,
%T 9888,10880,13392,14760,16392,17019,22366,24384,39424,57240,67488,
%U 68237,73276,93825,95728,106428,115330,128982,138176,143256,143780,144210,154432,156360
%N Numbers m such that m | A000385(m-1) = Sum_{k=1..m-1} sigma(k) * sigma(m-k).
%C 1 is in the sequence assuming A000385(0) = 0.
%C The corresponding quotients are 0, 2, 723, 3376, 7196, 48834, 116655, 222646, 263221, 294168, 865608, ...
%C Includes all the even perfect numbers except for 6 and 28.
%C The only prime number in the sequence is 3. This follows from formula for A000385 given by _Robert Israel_. - _Luis H. Gallardo_, Jun 17 2020
%H Amiram Eldar, <a href="/A326608/b326608.txt">Table of n, a(n) for n = 1..500</a>
%e 3 is in the sequence since 3 is a divisor for A000385(3-1) = 6.
%t aQ[n_] := Divisible[5 * DivisorSigma[3, n] - (6n - 1) * DivisorSigma[1, n], 12n]; Select[Range[2*10^5], aQ]
%Y Cf. A000203, A000385, A000396.
%K nonn
%O 1,2
%A _Amiram Eldar_, Oct 18 2019
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