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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 10 |
| 2 | 55 |
| 3 | 231 |
| 4 | 833 |
| 5 | 2720 |
| 6 | 8280 |
| 7 | 23920 |
| 8 | 66352 |
| 9 | 178176 |
| 10 | 465920 |
| 11 | 1191680 |
| 12 | 2991360 |
| 13 | 7389184 |
| 14 | 17999872 |
| 15 | 43315200 |
| 16 | 103116800 |
| 17 | 243138560 |
| 18 | 568393728 |
| 19 | 1318518784 |
| 20 | 3037265920 |
| 21 | 6952058880 |
| 22 | 15820390400 |
| 23 | 35809918976 |
| 24 | 80659611648 |
[1,10,55,231,833,2720,8280,23920,66352,178176, 465920,1191680,2991360,7389184,17999872,43315200, 103116800,243138560,568393728,1318518784, 3037265920,6952058880,15820390400,35809918976, 80659611648] |