A321567 - OEIS

The OEIS is supported by the many generous donors to the OEIS Foundation.

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give

A321567

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

1, 1, 1, 2, 3, 4, 6, 8, 11, 16, 21, 27, 38, 49, 63, 84, 109, 138, 180, 228, 289, 369, 463, 578, 732, 911, 1128, 1407, 1741, 2140, 2646, 3243, 3967, 4861, 5924, 7196, 8767, 10616, 12827, 15516, 18707, 22486, 27054, 32440, 38835, 46488, 55502, 66136, 78836, 93727, 111265

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,4

LINKS

Seiichi Manyama, Table of n, a(n) for n = 0..10000

FORMULA

G.f.: Product_{k>0} (1 + x^k)^A218320(k).

CROSSREFS

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).

Cf. A066806, A218320, A321566.

Sequence in context: A289432 A064660 A321359 * A066806 A271486 A226187

Adjacent sequences: A321564 A321565 A321566 * A321568 A321569 A321570

KEYWORD

nonn

AUTHOR

Seiichi Manyama, Nov 13 2018

STATUS

approved