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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 3 |
| 3 | 20 |
| 4 | 35 |
| 5 | 252 |
| 6 | 154 |
| 7 | 3432 |
| 8 | 6435 |
| 9 | 48620 |
| 10 | 92378 |
| 11 | 705432 |
| 12 | 676039 |
| 13 | 10400600 |
| 14 | 20058300 |
| 15 | 10341168 |
| 16 | 300540195 |
| 17 | 2333606220 |
| 18 | 1512522550 |
| 19 | 35345263800 |
| 20 | 6892326441 |
| 21 | 179419291480 |
| 22 | 1052049481860 |
| 23 | 8233430727600 |
| 24 | 2687300306925 |
| 25 | 126410606437752 |
| 26 | 247959266474052 |
[1,2,3,20,35,252,154,3432,6435,48620,92378,705432, 676039,10400600,20058300,10341168,300540195, 2333606220,1512522550,35345263800,6892326441, 179419291480,1052049481860,8233430727600, 2687300306925,126410606437752,247959266474052] |