%I #5 Mar 05 2018 17:45:39
%S 1,1,1,4,9,14,19,24,45,75,105,135,229,359,503,647,1047,1591,2272,2972,
%T 4696,6996,9844,12894,20064,29538,41204,54407,84457,123723,171757,
%U 225939,348643,508693,703815,923529,1423892,2076942,2870977,3763380,5778379,8414332,11621307
%N a(0) = a(1) = 1; a(n) = [x^n] Product_{k=1..n-1} 1/(1 - a(k)*x^a(k)).
%F G.f. A(x) = Sum_{n>=0} a(n)*x^n satisfies A(x) = -x - 2*x^2 + Product_{n>=1} 1/(1 - a(n)*x^a(n)).
%t a[n_] := a[n] = SeriesCoefficient[Product[1/(1 - a[k] x^a[k]), {k, 1, n - 1}], {x, 0, n}]; a[0] = a[1] = 1; Table[a[n], {n, 0, 42}]
%Y Cf. A006906, A093637, A151945, A196545, A291698, A293806, A293807, A296387.
%K nonn
%O 0,4
%A _Ilya Gutkovskiy_, Mar 05 2018
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