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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 3 |
| 4 | 4 |
| 5 | 5 |
| 6 | 6 |
| 7 | 7 |
| 8 | 15 |
| 9 | 23 |
| 10 | 50 |
| 11 | 114 |
| 12 | 330 |
| 13 | 1330 |
| 14 | 10591 |
| 15 | 215970 |
| 16 | 19464802 |
| 17 | 16542386125 |
| 18 | 409477218238718 |
| 19 | 1594640520554911022654 |
| 20 | 12254971660196485116306102211582 |
| 21 | 8256321288165573196207266557193504883194549246 |
[1,2,3,4,5,6,7,15,23,50,114,330,1330,10591,215970, 19464802,16542386125,409477218238718, 1594640520554911022654, 12254971660196485116306102211582, 8256321288165573196207266557193504883194549246] |