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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 14 |
| 3 | 132 |
| 4 | 1430 |
| 5 | 16796 |
| 6 | 208012 |
| 7 | 2674440 |
| 8 | 35357670 |
| 9 | 477638700 |
| 10 | 6564120420 |
| 11 | 91482563640 |
| 12 | 1289904147324 |
| 13 | 18367353072152 |
| 14 | 263747951750360 |
| 15 | 3814986502092304 |
| 16 | 55534064877048198 |
| 17 | 812944042149730764 |
| 18 | 11959798385860453492 |
| 19 | 176733862787006701400 |
[1,2,14,132,1430,16796,208012,2674440,35357670, 477638700,6564120420,91482563640,1289904147324, 18367353072152,263747951750360,3814986502092304, 55534064877048198,812944042149730764, 11959798385860453492,176733862787006701400] |