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A086990 as a simple table

na(n)
00
11
2-2
33
4-4
56
6-10
715
8-20
930
10-52
1178
12-96
13144
14-282
15423
16-420
17630
18-1660
192490
20-1304
211956
22-11332
2316998
243896
25-5844
26-95240
27142860
28157160
29-235740
30-983610
311475415
322634300
33-3951450
34-11751660
3517627490
3638381160
37-57571740

[0,1,-2,3,-4,6,-10,15,-20,30,-52,78,-96,144,-282,
 423,-420,630,-1660,2490,-1304,1956,-11332,16998,
 3896,-5844,-95240,142860,157160,-235740,-983610,
 1475415,2634300,-3951450,-11751660,17627490,
 38381160,-57571740]