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A009389 as a simple table

na(n)
00
11
2-1
33
4-4
55
6-1
77
8-64
99
101319
1111
12-49204
1313
142653559
1515
16-196707424
1717
1819194804719
1919
20-2385684870724
2121
22367985503366799
2323
24-68980888889771104
2525
2615445553274667315799
2727
28-4071626956018456576564
2929

[0,1,-1,3,-4,5,-1,7,-64,9,1319,11,-49204,13,
 2653559,15,-196707424,17,19194804719,19,
 -2385684870724,21,367985503366799,23,
 -68980888889771104,25,15445553274667315799,27,
 -4071626956018456576564,29]