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 A354022 #11 Sep 19 2023 17:11:55
%S A354022 1,-1,-5,-11,-119,241,-5039,-1679,-60479,1784161,-39916799,218877121,
%T A354022 -6227020799,43571848321,1078831353601,-518918399,-355687428095999,
%U A354022 1058152455360001,-121645100408831999,1115079416638387201,42565648051390464001,562000335730215782401
%N A354022 a(n) = n! * Sum_{d|n} mu(n/d) / d!.
%H A354022 Winston de Greef, <a href="/A354022/b354022.txt">Table of n, a(n) for n = 1..448</a>
%F A354022 E.g.f.: Sum_{k>=1} mu(k) * (exp(x^k) - 1).
%F A354022 Sum_{n>=1} a(n) * x^n / (n! * (1 - x^n)) = exp(x) - 1.
%t A354022 Table[n! Sum[MoebiusMu[n/d]/d!, {d, Divisors[n]}], {n, 1, 22}]
%t A354022 nmax = 22; CoefficientList[Series[Sum[MoebiusMu[k] (Exp[x^k] - 1), {k, 1, nmax}], {x, 0, nmax}], x] Range[0, nmax]! // Rest
%o A354022 (PARI) a(n)=n! * sumdiv(n, d, moebius(n/d) / d!) \\ _Winston de Greef_, Sep 19 2023
%Y A354022 Cf. A008683, A057625, A062794, A068107, A099740, A132958, A327243, A332466.
%K A354022 sign
%O A354022 1,3
%A A354022 _Ilya Gutkovskiy_, May 14 2022