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A369121 as a simple table

na(n)
0-1
11
2-1
33
4-1
55
6-15
7105
8-21
9105
10-315
112475
12-99
131001
14-1001
1515015
16-105105
1723205
18-663
191322685
20-101745
215595975
22-2611455
2360063465
24-1225785
2515935205
26-51555075
274686825
28-5368545
2940970475
30-40970475
31302703526125

[-1,1,-1,3,-1,5,-15,105,-21,105,-315,2475,-99,
 1001,-1001,15015,-105105,23205,-663,1322685,
 -101745,5595975,-2611455,60063465,-1225785,
 15935205,-51555075,4686825,-5368545,40970475,
 -40970475,302703526125]