%I #14 Mar 08 2020 10:15:52
%S 1,2,2,4,8,10,14,24,34,44,62,86,116,156,206,274,362,462,598,782,994,
%T 1258,1606,2018,2528,3178,3952,4904,6094,7490,9194,11322,13834,16836,
%U 20518,24880,30086,36366,43792,52656,63250,75626,90344,107926,128422,152546
%N Expansion of Product_{k>=1} (1 + x^sigma(k)) / (1 - x^sigma(k)).
%C Convolution of A111865 and A305321.
%t nmax = 50; CoefficientList[Series[Product[(1 + x^DivisorSigma[1, k])/(1 - x^DivisorSigma[1, k]), {k, 1, nmax}], {x, 0, nmax}], x]
%Y Cf. A000203, A111865, A305321.
%K nonn
%O 0,2
%A _Vaclav Kotesovec_, Mar 06 2020