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 A323407 #5 Jan 15 2019 18:43:14
%S A323407 1,-1,-2,-2,-4,2,-6,-2,-4,4,-10,4,-12,6,8,0,-16,4,-18,8,12,10,-22,4,
%T A323407 -8,12,-2,12,-28,-8,-30,4,20,16,24,8,-36,18,24,8,-40,-12,-42,20,16,22,
%U A323407 -46,0,-12,8,32,24,-52,2,40,12,36,28,-58,-16,-60,30,24,8,48,-20,-66,32,44,-24,-70,8,-72,36,16,36,60,-24,-78,0,8,40,-82,-24
%N A323407 Dirichlet inverse of A047994, unitary phi.
%H A323407 Antti Karttunen, <a href="/A323407/b323407.txt">Table of n, a(n) for n = 1..20000</a>
%o A323407 (PARI)
%o A323407 up_to = 65537;
%o A323407 DirInverse(v) = { my(u=vector(#v)); u[1] = (1/v[1]); for(n=2, #v, u[n] = -sumdiv(n, d, if(d<n, v[n/d]*u[d], 0))); (u) }; \\ Compute the Dirichlet inverse of the sequence given in input vector v.
%o A323407 A047994(n)=my(f=factor(n)~); prod(i=1, #f, f[1, i]^f[2, i]-1);
%o A323407 v323407 = DirInverse(vector(up_to,n,A047994(n)));
%o A323407 A323407(n) = v323407[n];
%Y A323407 Cf. A047994, A323408.
%Y A323407 Cf. also A023900.
%K A323407 sign
%O A323407 1,3
%A A323407 _Antti Karttunen_, Jan 15 2019