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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 4 |
| 5 | 10 |
| 6 | 26 |
| 7 | 70 |
| 8 | 200 |
| 9 | 602 |
| 10 | 1904 |
| 11 | 6317 |
| 12 | 21886 |
| 13 | 78911 |
| 14 | 295259 |
| 15 | 1143535 |
| 16 | 4574143 |
| 17 | 18859677 |
| 18 | 80014834 |
| 19 | 348776576 |
| 20 | 1559776268 |
| 21 | 7147792818 |
| 22 | 33526120082 |
| 23 | 160785623545 |
| 24 | 787685471322 |
| 25 | 3938427356614 |
| 26 | 20082117944245 |
| 27 | 104349745809073 |
| 28 | 552166953567228 |
| 29 | 2973510046012910 |
| 30 | 16286585271694955 |
| 31 | 90679869067935485 |
[1,1,1,2,4,10,26,70,200,602,1904,6317,21886,78911, 295259,1143535,4574143,18859677,80014834, 348776576,1559776268,7147792818,33526120082, 160785623545,787685471322,3938427356614, 20082117944245,104349745809073,552166953567228, 2973510046012910,16286585271694955, 90679869067935485] |