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 A244342 #27 Apr 08 2020 11:18:49
%S A244342 1,2,6,8,12,12,18,32,30,24,30,48,36,36,72,96,48,60,54,96,108,60,66,
%T A244342 192,100,72,126,144,84,144,90,256,180,96,216,240,108,108,216,384,120,
%U A244342 216,126,240,360,132,138,576,210,200,288,288,156,252,360,576,324,168
%N A244342 a(n) = phi(n)*h(n) where phi() is the Euler totient function, A000010, and h() is A092089.
%C A244342 a(n) = Sum_{k=1..n} gcd(k^2-1, n) for those k that are coprime to n (see proof in link).
%C A244342 Multiplicative because both A000010 and A092089 are. - _Andrew Howroyd_, Jul 26 2018
%H A244342 Robert Israel, <a href="/A244342/b244342.txt">Table of n, a(n) for n = 1..10000</a>
%H A244342 László Tóth, <a href="http://www.seminariomatematico.polito.it/rendiconti/69-1/97.pdf">Menon's identity and arithmetical sums representing functions of several variables</a>, Rend. Sem. Mat. Univ. Politec. Torino, 69 (2011), 97-110 (see (36) in Corollary 15, p. 108); also on <a href="https://arxiv.org/abs/1103.5861">arXiv</a>, arXiv:1103.5861 [math.NT], 2011.
%p A244342 A244342:= proc(n) add(`if`(igcd(k,n)=1,igcd(k^2-1,n),0),k=1..n) end proc;
%p A244342 seq(A244342(i),i=1..1000); # _Robert Israel_, Jul 06 2014
%t A244342 h[n_] := Product[{p, e} = pe; Which[OddQ[p], 2 e + 1, p == 2 && e == 1, 2, True, 4 (e - 1)], {pe, FactorInteger[n]}]; h[1] = 1;
%t A244342 a[n_] := EulerPhi[n] h[n];
%t A244342 Array[a, 100] (* _Jean-François Alcover_, Apr 08 2020 *)
%o A244342 (PARI) a(n) = sum(j=1, n, gcd(j^2-1,n)*(gcd(j,n)==1));
%Y A244342 Cf. A000010, A062355, A092089.
%K A244342 nonn,mult
%O A244342 1,2
%A A244342 _Michel Marcus_, Jun 26 2014