%I #8 Nov 13 2018 12:51:02
%S 1,1,1,2,3,4,6,8,11,16,21,27,38,49,63,84,109,138,180,228,289,369,463,
%T 578,732,911,1128,1407,1741,2140,2646,3243,3967,4861,5924,7196,8767,
%U 10616,12827,15516,18707,22486,27054,32440,38835,46488,55502,66136,78836,93727,111265
%N Expansion of Product_{1 <= i_1 <= i_2 <= i_3 <= i_4} (1 + x^(i_1*i_2*i_3*i_4)).
%H Seiichi Manyama, <a href="/A321567/b321567.txt">Table of n, a(n) for n = 0..10000</a>
%F G.f.: Product_{k>0} (1 + x^k)^A218320(k).
%Y Product_{1 <= i_1 <= i_2 <= ... <= i_b} (1 + x^(i_1 * i_2 * ... * i_b)): A000009 (b=1), A211856 (b=2), A321359 (b=3), this sequence (b=4).
%Y Cf. A066806, A218320, A321566.
%K nonn
%O 0,4
%A _Seiichi Manyama_, Nov 13 2018
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