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A321567 Expansion of Product_{1 <= i_1 <= i_2 <= i_3 <= i_4} (1 + x^(i_1*i_2*i_3*i_4)). 3

%I

%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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Last modified July 6 23:56 EDT 2020. Contains 335484 sequences. (Running on oeis4.)