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| n | a(n) |
|---|---|
| 0 | -1 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | -3 |
| 5 | -20 |
| 6 | -70 |
| 7 | -84 |
| 8 | 1267 |
| 9 | 18824 |
| 10 | 209484 |
| 11 | 2284920 |
| 12 | 26010369 |
| 13 | 314864628 |
| 14 | 4073158102 |
| 15 | 56304102596 |
| 16 | 830061867975 |
| 17 | 13016975343184 |
| 18 | 216535182535928 |
| 19 | 3810394068301296 |
| 20 | 70744547160678501 |
| 21 | 1382375535029293500 |
| 22 | 28364229790262962386 |
| 23 | 609820072529413714012 |
[-1,0,0,0,-3,-20,-70,-84,1267,18824,209484, 2284920,26010369,314864628,4073158102,56304102596, 830061867975,13016975343184,216535182535928, 3810394068301296,70744547160678501, 1382375535029293500,28364229790262962386, 609820072529413714012] |