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 A070943 #20 Oct 30 2022 05:27:51
%S A070943 1,18,384,1344,11520,6912,96768,92160,303264,207360,1584000,516096,
%T A070943 4402944,1741824,4423680,6094848,22560768,5458752,44323200,15482880,
%U A070943 37158912,28512000,141064704,35389440,186000000,79252992,226748160,130056192,572947200,79626240
%N A070943 Commuting elements: number of ordered pairs g, h in the group GL(2,Z_n) such that gh = hg.
%H A070943 Eric M. Schmidt, <a href="/A070943/b070943.txt">Table of n, a(n) for n = 1..1000</a>
%F A070943 a(n) = A000252(n) * A062354(n).
%F A070943 a(n) = n^4 * Product_{p prime, p|n} (1-1/p^2)*(1-1/p) * sigma(n)*phi(n).
%F A070943 From _Amiram Eldar_, Oct 30 2022: (Start)
%F A070943 Multiplicative with a(p^e) = (p^(e+1)-1) * (p-1)^2 * (p+1) * p^(5*e-4).
%F A070943 Sum_{k=1..n} a(k) ~ c * n^7, where c = (1/7) * Product_{p prime} (1 - 1/p^2 - 2/p^3 + 3/p^4 - 1/p^5) = 0.07103214283... . (End)
%t A070943 a[n_] := n^4*DivisorSigma[1, n]*EulerPhi[n]*Product[(1-1/p^2)*(1-1/p), {p, FactorInteger[n][[All, 1]]}]; a[1]=1; Table[a[n], {n, 1, 30}] (* _Jean-François Alcover_, May 02 2013, after _Eric M. Schmidt_ *)
%o A070943 (Sage)
%o A070943 def A070943(n) : return Integer(n^4 * sigma(n) * euler_phi(n) * prod((1-1/p^2)*(1-1/p) for (p,m) in factor(n))) # _Eric M. Schmidt_, May 02 2013
%Y A070943 Cf. A000010, A000203, A000252, A062354.
%K A070943 mult,nonn
%O A070943 1,2
%A A070943 Yuval Dekel (dekelyuval(AT)hotmail.com), Sep 12 2003
%E A070943 More terms from _Benoit Cloitre_, Sep 13 2003
%E A070943 More terms from _Eric M. Schmidt_, May 02 2013