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 A071707 #15 Apr 16 2025 04:37:38
%S A071707 1,2,6,12,18,24,28,40,84,120,224,234,240,252,360,468,496,672,864,936,
%T A071707 1638,1920,2016,2480,3276,4320,4680,6048,6528,6552,7440,8128,9360,
%U A071707 10880,22320,22932,26208,30240,32640,32760,47616,56896,58752,65520,74880,79360,84480
%N A071707 Numbers k that divide tau(k)*sigma(k).
%H A071707 Donovan Johnson, <a href="/A071707/b071707.txt">Table of n, a(n) for n = 1..300</a>
%e A071707 The divisors of 18 are {1,2,3,6,9,18}, so tau(18) = 6 and sigma(18) = 1+2+3+6+9+18 = 39, 18 is a term as 18*13 = 6*39 = tau(18)*sigma(18).
%t A071707 Select[Range[10^5], Divisible[Times @@ DivisorSigma[{0, 1}, #], #] &] (* _Amiram Eldar_, Apr 16 2025 *)
%o A071707 (PARI) isok(k) = {my(f = factor(k)); !((numdiv(f) * sigma(f)) % k);} \\ _Amiram Eldar_, Apr 16 2025
%Y A071707 A007691 is a subsequence.
%Y A071707 Cf. A064840 (A000005(n)*A000203(n)).
%K A071707 nonn
%O A071707 1,2
%A A071707 _Reinhard Zumkeller_, Jun 03 2002