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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 2 |
| 5 | 7 |
| 6 | 15 |
| 7 | 39 |
| 8 | 81 |
| 9 | 193 |
| 10 | 396 |
| 11 | 885 |
| 12 | 1816 |
| 13 | 3915 |
| 14 | 7973 |
| 15 | 16860 |
| 16 | 34165 |
| 17 | 71092 |
| 18 | 143804 |
| 19 | 295963 |
| 20 | 596872 |
| 21 | 1219950 |
| 22 | 2455139 |
| 23 | 4989265 |
| 24 | 10028841 |
| 25 | 20296288 |
| 26 | 40745616 |
| 27 | 82225558 |
| 28 | 164916967 |
| 29 | 332045545 |
| 30 | 665566046 |
| 31 | 1337794545 |
| 32 | 2680049287 |
| 33 | 5380396625 |
| 34 | 10774301183 |
[1,0,0,1,2,7,15,39,81,193,396,885,1816,3915,7973, 16860,34165,71092,143804,295963,596872,1219950, 2455139,4989265,10028841,20296288,40745616, 82225558,164916967,332045545,665566046,1337794545, 2680049287,5380396625,10774301183] |