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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | -1 |
| 2 | -1 |
| 3 | -1 |
| 4 | 0 |
| 5 | -2 |
| 6 | -4 |
| 7 | -4 |
| 8 | -8 |
| 9 | -10 |
| 10 | -17 |
| 11 | -10 |
| 12 | 6 |
| 13 | 45 |
| 14 | 260 |
| 15 | 604 |
| 16 | 1285 |
| 17 | 3329 |
| 18 | 6755 |
| 19 | 12550 |
| 20 | 25790 |
| 21 | 46302 |
| 22 | 75922 |
| 23 | 129739 |
| 24 | 188164 |
| 25 | 215880 |
| 26 | 177637 |
| 27 | -208052 |
| 28 | -1480885 |
| 29 | -4563499 |
| 30 | -11984644 |
| 31 | -28275270 |
| 32 | -61059278 |
| 33 | -126088969 |
| 34 | -248020723 |
| 35 | -462216478 |
| 36 | -823834918 |
| 37 | -1383451194 |
| 38 | -2136524063 |
[1,-1,-1,-1,0,-2,-4,-4,-8,-10,-17,-10,6,45,260, 604,1285,3329,6755,12550,25790,46302,75922,129739, 188164,215880,177637,-208052,-1480885,-4563499, -11984644,-28275270,-61059278,-126088969, -248020723,-462216478,-823834918,-1383451194, -2136524063] |