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 A326937 #16 Dec 02 2020 03:15:28
%S A326937 1,-1,-3,0,-5,3,-7,0,0,5,-11,0,-13,7,15,0,-17,0,-19,0,21,11,-23,0,0,
%T A326937 13,0,0,-29,-15,-31,0,33,17,35,0,-37,19,39,0,-41,-21,-43,0,0,23,-47,0,
%U A326937 0,0,51,0,-53,0,55,0,57,29,-59,0,-61,31,0,0,65,-33,-67,0,69,-35,-71,0,-73,37,0
%N A326937 Dirichlet g.f.: (2^s - 1) / (zeta(s-1) * (2^s - 2)).
%C A326937 Dirichlet inverse of A000265.
%H A326937 Amiram Eldar, <a href="/A326937/b326937.txt">Table of n, a(n) for n = 1..10000</a>
%F A326937 a(1) = 1; a(n) = -Sum_{d|n, d<n} A000265(n/d) * a(d).
%F A326937 a(n) = A055615(n) / A006519(n).
%F A326937 Multiplicative with a(p) = -1 for p = 2 and -p for odd primes p, and a(p^e) = 0 if e > 1. - _Amiram Eldar_, Dec 02 2020
%t A326937 a[1] = 1; a[n_] := -Sum[(n/d)/2^IntegerExponent[n/d, 2] a[d], {d, Most @ Divisors[n]}]; Table[a[n], {n, 1, 75}]
%t A326937 Table[MoebiusMu[n] n/2^IntegerExponent[n, 2], {n, 1, 75}]
%t A326937 f[2, e_] := -Boole[e == 1]; f[p_, e_] := -Boole[e == 1]*p; a[1] = 1; a[n_] := Times @@ (f @@@ FactorInteger[n]); Array[a, 100] (* _Amiram Eldar_, Dec 02 2020 *)
%o A326937 (PARI) a(n)={n*moebius(n)/2^valuation(n,2)} \\ _Andrew Howroyd_, Oct 25 2019
%Y A326937 Cf. A000265, A006519, A013929 (positions of 0's), A030059 (positions of negative terms), A055615.
%K A326937 sign,mult
%O A326937 1,3
%A A326937 _Ilya Gutkovskiy_, Oct 22 2019