|
%I #5 Nov 15 2019 21:35:44
%S 1,2,3,4,3,8,5,8,9,11,8,20,12,17,20,25,18,36,25,38,39,44,37,68,51,63,
%T 69,85,69,113,90,117,117,136,128,189,154,185,195,239,206,288,253,308,
%U 321,358,333,457,406,476,485,566,521,671,629,734,737,833,794,1019
%N Expansion of Sum_{k>=1} (-1 + Product_{j>=1} 1 / (1 - x^(k*j*(j + 1)/2))).
%C Inverse Moebius transform of A007294.
%F G.f.: Sum_{k>=1} A007294(k) * x^k / (1 - x^k).
%F a(n) = Sum_{d|n} A007294(d).
%t nmax = 60; CoefficientList[Series[Sum[-1 + Product[1/(1 - x^(k j (j + 1)/2)), {j, 1, nmax}], {k, 1, nmax}], {x, 0, nmax}], x] // Rest
%Y Cf. A007294, A047966, A047968, A329439, A329466.
%K nonn
%O 1,2
%A _Ilya Gutkovskiy_, Nov 13 2019
|
