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%I #19 May 11 2019 18:32:28
%S 1,1,1,1,3,3,6,5,11,8,14,16,20,16,37,22,34,49,44,36,90,46,73,108,80,
%T 75,181,89,121,210,151,123,334,153,197,368,227,219,567,229,313,613,
%U 365,315,871,367,461,986,519,463,1355,534,660,1429,756,662,1960,794,940,2054
%N G.f. A(x) satisfies: A(x) = x + x^2 + x^3 * (1 + Sum_{i>=1} Sum_{j>=1} A(x^(i*j))).
%C Shifts 3 places left when inverse Moebius transform applied twice.
%F a(1) = a(2) = a(3) = 1; a(n+3) = Sum_{d|n} tau(n/d)*a(d), where tau = number of divisors (A000005).
%t a[n_] := a[n] = Sum[DivisorSigma[0, (n - 3)/d] a[d], {d, Divisors[n - 3]}]; a[1] = a[2] = a[3] = 1; Table[a[n], {n, 1, 60}]
%Y Cf. A000005, A007557, A307982, A307993, A308083, A319133.
%K nonn
%O 1,5
%A _Ilya Gutkovskiy_, May 11 2019
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