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 A174940 #13 Sep 08 2022 08:45:51
%S A174940 1,1,2,6,4,32,6,56,24,94,10,1686,12,188,218,960,16,5772,18,7894,432,
%T A174940 472,22,329992,120,662,702,21750,28,809648,30,31744,1076,1138,1214,
%U A174940 10070172,36,1424,1506,2551944,40,3111034,42,84694,90876,2092,46,254471232,336,124780
%N A174940 a(n) = Sum_{d|n} A007955(d) * A008683(n/d) = Sum_{d|n} A007955(d) * mu(n/d), where A007955(m) = number of divisors of m.
%H A174940 Andrew Howroyd, <a href="/A174940/b174940.txt">Table of n, a(n) for n = 1..1000</a>
%F A174940 Moebius transform of A007955. - _Andrew Howroyd_, Jan 05 2020
%e A174940 For n = 4, A007955(n) = b(n): a(4) = b(1)*mu(4/1) + b(2)*mu(4/2) + b(4)*mu(4/4) = 1*0 + 2*(-1) + 8*1 = 6.
%t A174940 a[n_] := Sum[ MoebiusMu[n/d] * Times @@ Divisors[d], {d, Divisors[n]} ]; Table[ a[n], {n, 1, 30} ] (* _Jean-François Alcover_, Jan 09 2013 *)
%o A174940 (PARI) a(n)={sumdiv(n, d, vecprod(divisors(d))*moebius(n/d))} \\ _Andrew Howroyd_, Jan 05 2020
%o A174940 (Magma) [&+[&*Divisors(d)*MoebiusMu(n div d):d in Divisors(n)]:n in [1..50]]; // _Marius A. Burtea_, Jan 05 2020
%Y A174940 Cf. A008683 (mu), A007955 (product of divisors).
%K A174940 nonn
%O A174940 1,3
%A A174940 _Jaroslav Krizek_, Apr 02 2010
%E A174940 Terms a(31) and beyond from _Andrew Howroyd_, Jan 05 2020