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| n | a(n) |
|---|---|
| 2 | 1 |
| 3 | 2 |
| 4 | 4 |
| 5 | 14 |
| 6 | 38 |
| 7 | 132 |
| 8 | 420 |
| 9 | 1426 |
| 10 | 4834 |
| 11 | 16796 |
| 12 | 58688 |
| 13 | 208012 |
| 14 | 742636 |
| 15 | 2674384 |
| 16 | 9693976 |
| 17 | 35357670 |
| 18 | 129641774 |
| 19 | 477638700 |
| 20 | 1767253368 |
| 21 | 6564119892 |
| 22 | 24466233428 |
| 23 | 91482563640 |
| 24 | 343059494120 |
| 25 | 1289904147128 |
| 26 | 4861945985428 |
| 27 | 18367353066440 |
| 28 | 69533549429280 |
| 29 | 263747951750360 |
[1,2,4,14,38,132,420,1426,4834,16796,58688,208012, 742636,2674384,9693976,35357670,129641774, 477638700,1767253368,6564119892,24466233428, 91482563640,343059494120,1289904147128, 4861945985428,18367353066440,69533549429280, 263747951750360] |