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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 2 |
| 2 | 3 |
| 3 | 10 |
| 4 | 24 |
| 5 | 65 |
| 6 | 168 |
| 7 | 442 |
| 8 | 1155 |
| 9 | 3026 |
| 10 | 7920 |
| 11 | 20737 |
| 12 | 54288 |
| 13 | 142130 |
| 14 | 372099 |
| 15 | 974170 |
| 16 | 2550408 |
| 17 | 6677057 |
| 18 | 17480760 |
| 19 | 45765226 |
| 20 | 119814915 |
| 21 | 313679522 |
| 22 | 821223648 |
| 23 | 2149991425 |
| 24 | 5628750624 |
| 25 | 14736260450 |
| 26 | 38580030723 |
| 27 | 101003831722 |
| 28 | 264431464440 |
| 29 | 692290561601 |
[0,2,3,10,24,65,168,442,1155,3026,7920,20737, 54288,142130,372099,974170,2550408,6677057, 17480760,45765226,119814915,313679522,821223648, 2149991425,5628750624,14736260450,38580030723, 101003831722,264431464440,692290561601] |