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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 12 |
| 5 | 30 |
| 6 | 100 |
| 7 | 285 |
| 8 | 1018 |
| 9 | 3142 |
| 10 | 11736 |
| 11 | 38276 |
| 12 | 147552 |
| 13 | 501072 |
| 14 | 1977608 |
| 15 | 6926828 |
| 16 | 27842000 |
| 17 | 99938263 |
| 18 | 407596014 |
| 19 | 1492448436 |
| 20 | 6159941412 |
| 21 | 22930113936 |
| 22 | 95587448784 |
| 23 | 360799985580 |
| 24 | 1516761327208 |
| 25 | 5793529219084 |
| 26 | 24531896869176 |
| 27 | 94672009465506 |
| 28 | 403396322741868 |
| 29 | 1570813436684425 |
| 30 | 6730083531676042 |
[1,1,2,4,12,30,100,285,1018,3142,11736,38276, 147552,501072,1977608,6926828,27842000,99938263, 407596014,1492448436,6159941412,22930113936, 95587448784,360799985580,1516761327208, 5793529219084,24531896869176,94672009465506, 403396322741868,1570813436684425,6730083531676042] |