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 A338656 #24 Apr 23 2021 11:58:44
%S A338656 1,0,0,-1,0,-4,0,-3,-5,-8,0,-9,0,-12,-28,-7,0,-8,0,-34,-54,-20,0,9,
%T A338656 -69,-24,-44,-83,0,0,0,-15,-130,-32,-418,157,0,-36,-180,-129,0,0,0,
%U A338656 -285,-494,-44,0,633,-923,-24,-304,-454,0,1090,-2000,-1183,-378,-56,0,3050,0,-60,-3002,-31,-3638,0
%N A338656 a(n) = Sum_{d|n} mu(d) * binomial(d + n/d - 2, d-1).
%H A338656 Seiichi Manyama, <a href="/A338656/b338656.txt">Table of n, a(n) for n = 1..10000</a>
%F A338656 G.f.: Sum_{k >= 1} mu(k) * (x/(1 - x^k))^k.
%F A338656 If p is prime, a(p) = 0.
%t A338656 a[n_] := DivisorSum[n, MoebiusMu[#] * Binomial[# + n/# - 2, # - 1] &]; Array[a, 100] (* _Amiram Eldar_, Apr 22 2021 *)
%o A338656 (PARI) a(n) = sumdiv(n, d, moebius(d)*binomial(d+n/d-2, d-1));
%o A338656 (PARI) my(N=66, x='x+O('x^N)); Vec(sum(k=1, N, moebius(k)*(x/(1-x^k))^k))
%Y A338656 Cf. A008683, A157020, A332470, A338657.
%K A338656 sign,look
%O A338656 1,6
%A A338656 _Seiichi Manyama_, Apr 22 2021