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 A359601 #12 Jan 11 2023 20:59:45
%S A359601 1,0,-3,-4,-3,0,-1,0,0,-10,-9,12,-13,-12,9,6,-9,0,-1,24,3,-4,-3,0,8,0,
%T A359601 0,-20,-27,30,-31,-30,27,-28,-21,0,-37,-36,39,40,-39,36,-37,36,0,-28,
%U A359601 -27,-18,-30,30,27,76,-27,0,53,96,3,-4,-3,-72,-1,0,0,6,69,12,-13,60,9,82,-9,0,-1,0,-24,4,15
%N A359601 Dirichlet inverse of A244042, where A244042(n) replaces 2's with 0's in the ternary representation of n.
%H A359601 Antti Karttunen, <a href="/A359601/b359601.txt">Table of n, a(n) for n = 1..19683</a>
%F A359601 a(1) = 1, and for n > 1, a(n) = -Sum_{d|n, d<n} A244042(n/d) * a(d).
%F A359601 a(n) = A359602(n) - A244042(n).
%o A359601 (PARI)
%o A359601 A244042(n) = fromdigits(apply(x->(x%2), digits(n, 3)), 3);
%o A359601 memoA359601 = Map();
%o A359601 A359601(n) = if(1==n,1,my(v); if(mapisdefined(memoA359601,n,&v), v, v = -sumdiv(n,d,if(d<n,A244042(n/d)*A359601(d),0)); mapput(memoA359601,n,v); (v)));
%Y A359601 Cf. A244042, A300821, A359602.
%Y A359601 Cf. A056911 (positions of odd terms), A323239 (parity of terms), A337945.
%K A359601 sign,base,easy,look
%O A359601 1,3
%A A359601 _Antti Karttunen_, Jan 11 2023