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| n | a(n) |
|---|---|
| 0 | -1 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 4 |
| 6 | 6 |
| 7 | 12 |
| 8 | 24 |
| 9 | 42 |
| 10 | 68 |
| 11 | 122 |
| 12 | 208 |
| 13 | 336 |
| 14 | 552 |
| 15 | 904 |
| 16 | 1464 |
| 17 | 2378 |
| 18 | 3848 |
| 19 | 6232 |
| 20 | 10090 |
| 21 | 16338 |
| 22 | 26446 |
| 23 | 42802 |
| 24 | 69252 |
| 25 | 112072 |
| 26 | 181332 |
| 27 | 293412 |
| 28 | 474762 |
| 29 | 768190 |
| 30 | 1242960 |
| 31 | 2011162 |
| 32 | 3254150 |
| 33 | 5265324 |
| 34 | 8519478 |
| 35 | 13784866 |
| 36 | 22304378 |
| 37 | 36089262 |
| 38 | 58393658 |
| 39 | 94482964 |
| 40 | 152876664 |
[-1,0,0,0,0,4,6,12,24,42,68,122,208,336,552,904, 1464,2378,3848,6232,10090,16338,26446,42802,69252, 112072,181332,293412,474762,768190,1242960, 2011162,3254150,5265324,8519478,13784866,22304378, 36089262,58393658,94482964,152876664] |