This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A326608 #21 Jul 08 2020 21:36:26 %S A326608 1,3,40,84,124,318,496,672,732,790,1320,1488,3154,4464,5271,8128,9156, %T A326608 9888,10880,13392,14760,16392,17019,22366,24384,39424,57240,67488, %U A326608 68237,73276,93825,95728,106428,115330,128982,138176,143256,143780,144210,154432,156360 %N A326608 Numbers m such that m | A000385(m-1) = Sum_{k=1..m-1} sigma(k) * sigma(m-k). %C A326608 1 is in the sequence assuming A000385(0) = 0. %C A326608 The corresponding quotients are 0, 2, 723, 3376, 7196, 48834, 116655, 222646, 263221, 294168, 865608, ... %C A326608 Includes all the even perfect numbers except for 6 and 28. %C A326608 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 A326608 Amiram Eldar, <a href="/A326608/b326608.txt">Table of n, a(n) for n = 1..500</a> %e A326608 3 is in the sequence since 3 is a divisor for A000385(3-1) = 6. %t A326608 aQ[n_] := Divisible[5 * DivisorSigma[3, n] - (6n - 1) * DivisorSigma[1, n], 12n]; Select[Range[2*10^5], aQ] %Y A326608 Cf. A000203, A000385, A000396. %K A326608 nonn %O A326608 1,2 %A A326608 _Amiram Eldar_, Oct 18 2019