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 A307740 #14 Sep 08 2022 08:46:21
%S A307740 1,2,6,12,24,28,40,84,120,252,360,496,672,2480,3276,4680,7440,8128,
%T A307740 30240,32760,56896,293760,435708,523776,997920,2178540,2618880,
%U A307740 8910720,23569920,33550336,45532800,64995840,102136320,142990848,275890944,436154368,459818240
%N A307740 Numbers k such that k divides lcm(tau(k), sigma(k)).
%C A307740 Numbers k such that k divides A009278(k).
%C A307740 Conjecture: multiply-perfect numbers (A007691) are terms.
%C A307740 Corresponding values of lcm(tau(k), sigma(k)) / k for numbers k from this sequence: 1, 3, 2, 7, 5, 6, 9, 8, 6, 26, 13, 10, 3, 12, 28, 14, 16, 14, 4, ...
%C A307740 Sequence of the smallest numbers k such that lcm(tau(k), sigma(k)) / k = n for n >= 1: 1, 6, 2, 30240, 24, 28, 12, 84, 40, 496, ...
%e A307740 6 is in the sequence because lcm(tau(6), sigma(6)) / 6 = lcm(4, 12) / 6 = 12 / 6 = 2.
%t A307740 aQ[n_]:=Divisible[LCM@@(DivisorSigma[#,n]&/@{0,1}),n]; Select[Range[10000], aQ] (* _Amiram Eldar_, May 07 2019 *)
%o A307740 (Magma) [n: n in [1..1000000] | LCM(SumOfDivisors(n), NumberOfDivisors(n)) mod n eq 0]
%o A307740 (PARI) isok(n) = !(lcm(numdiv(n), sigma(n)) % n); \\ _Michel Marcus_, Apr 26 2019
%Y A307740 Cf. A000005, A000203, A007691, A009278.
%K A307740 nonn
%O A307740 1,2
%A A307740 _Jaroslav Krizek_, Apr 26 2019
%E A307740 More terms from _Amiram Eldar_, May 07 2019