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 A281573 #4 Jan 24 2017 20:29:58
%S A281573 1,3,6,11,19,33,51,79,118,176,252,362,505,705,965,1314,1765,2365,3127,
%T A281573 4124,5387,7012,9052,11653,14893,18982,24048,30378,38176,47857,59704,
%U A281573 74302,92099,113879,140300,172463,211297,258325,314887,383037,464684,562653,679566,819269,985449,1183242,1417738,1695886
%N A281573 Expansion of Sum_{i>=1} mu(i)^2*x^i/(1 - x^i) / Product_{j>=1} (1 - x^j), where mu() is the Moebius function (A008683).
%C A281573 Total number of squarefree parts in all partitions of n.
%C A281573 Convolution of A000041 and A034444.
%H A281573 <a href="/index/Par#partN">Index entries for related partition-counting sequences</a>
%F A281573 G.f.: Sum_{i>=1} mu(i)^2*x^i/(1 - x^i) / Product_{j>=1} (1 - x^j).
%e A281573 a(5) = 19 because we have [5], [4, 1], [3, 2], [3, 1, 1], [2, 2, 1], [2, 1, 1, 1], [1, 1, 1, 1, 1] and 1 + 1 + 2 + 3 + 3 + 4 + 5 = 19.
%t A281573 nmax = 48; Rest[CoefficientList[Series[Sum[MoebiusMu[i]^2 x^i/(1 - x^i), {i, 1, nmax}]/Product[1 - x^j, {j, 1, nmax}], {x, 0, nmax}], x]]
%Y A281573 Cf. A000041, A005117, A008683, A034444, A037032, A073335, A073336.
%K A281573 nonn
%O A281573 1,2
%A A281573 _Ilya Gutkovskiy_, Jan 24 2017