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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 16 |
| 5 | 45 |
| 6 | 142 |
| 7 | 452 |
| 8 | 1429 |
| 9 | 4706 |
| 10 | 15830 |
| 11 | 53092 |
| 12 | 180380 |
| 13 | 622747 |
| 14 | 2155976 |
| 15 | 7495821 |
| 16 | 26308397 |
| 17 | 92778770 |
| 18 | 327973373 |
| 19 | 1165333486 |
| 20 | 4159080037 |
| 21 | 14877633175 |
| 22 | 53376247653 |
| 23 | 192149069209 |
| 24 | 693285668555 |
| 25 | 2506469460691 |
| 26 | 9083812061880 |
| 27 | 32988452185659 |
| 28 | 119995516195356 |
| 29 | 437257636411965 |
| 30 | 1596078045075818 |
[1,1,2,6,16,45,142,452,1429,4706,15830,53092, 180380,622747,2155976,7495821,26308397,92778770, 327973373,1165333486,4159080037,14877633175, 53376247653,192149069209,693285668555, 2506469460691,9083812061880,32988452185659, 119995516195356,437257636411965,1596078045075818] |