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 A355693 #8 Jul 18 2022 16:39:20
%S A355693 1,-1,-1,0,-1,0,-1,0,0,1,-1,1,-1,1,-1,0,-1,1,-1,0,1,1,-1,0,0,1,0,0,-1,
%T A355693 0,-1,0,1,1,-3,-2,-1,1,1,0,-1,0,-1,0,2,1,-1,0,0,0,1,0,-1,0,1,0,1,1,-1,
%U A355693 1,-1,1,0,0,1,0,-1,0,1,3,-1,1,-1,1,2,0,-5,0,-1,0,0,1,-1,-1,1,1,1,0,-1,3,1,0,1,1,1,0
%N A355693 Dirichlet inverse of A330749, gcd(n, A064989(n)), where A064989 shifts the prime factorization one step towards lower primes.
%H A355693 Antti Karttunen, <a href="/A355693/b355693.txt">Table of n, a(n) for n = 1..65537</a>
%H A355693 <a href="/index/Pri#prime_indices">Index entries for sequences computed from indices in prime factorization</a>
%F A355693 a(1) = 1, and for n > 1, a(n) = -Sum_{d|n, d<n} A330749(n/d) * a(d).
%o A355693 (PARI)
%o A355693 A330749(n) = {my(f); f = factor(n); if((n>1 && f[1, 1]==2), f[1, 2] = 0); for (i=1, #f~, f[i, 1] = precprime(f[i, 1]-1)); gcd(n, factorback(f)); };
%o A355693 memoA355693 = Map();
%o A355693 A355693(n) = if(1==n,1,my(v); if(mapisdefined(memoA355693,n,&v), v, v = -sumdiv(n,d,if(d<n,A330749(n/d)*A355693(d),0)); mapput(memoA355693,n,v); (v)));
%Y A355693 Cf. A064989, A330749.
%Y A355693 Cf. also A354365, A354366.
%K A355693 sign
%O A355693 1,35
%A A355693 _Antti Karttunen_, Jul 18 2022