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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 10 |
| 5 | 32 |
| 6 | 116 |
| 7 | 368 |
| 8 | 1235 |
| 9 | 4321 |
| 10 | 13396 |
| 11 | 40668 |
| 12 | 124627 |
| 13 | 362283 |
| 14 | 1030513 |
| 15 | 2887111 |
| 16 | 7874749 |
| 17 | 21054468 |
| 18 | 55326873 |
| 19 | 142607396 |
| 20 | 361404953 |
| 21 | 901518960 |
| 22 | 2213631284 |
| 23 | 5356287900 |
| 24 | 12780944283 |
| 25 | 30087543948 |
| 26 | 69923248394 |
| 27 | 160510425840 |
[1,1,3,10,32,116,368,1235,4321,13396,40668,124627, 362283,1030513,2887111,7874749,21054468,55326873, 142607396,361404953,901518960,2213631284, 5356287900,12780944283,30087543948,69923248394, 160510425840] |