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A009431 as a simple table

na(n)
00
11
2-1
3-1
40
549
6-165
7-393
8-504
970785
10-434385
11-517265
12-12647976
13654552625
14-6276987717
1518362076327
16-636272644560
1722683808563841
18-312594994151361
192817355930176479
20-72112751626318640
212222078368780722865

[0,1,-1,-1,0,49,-165,-393,-504,70785,-434385,
 -517265,-12647976,654552625,-6276987717,
 18362076327,-636272644560,22683808563841,
 -312594994151361,2817355930176479,
 -72112751626318640,2222078368780722865]