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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 10 |
| 4 | 35 |
| 5 | 124 |
| 6 | 430 |
| 7 | 1647 |
| 8 | 6183 |
| 9 | 23789 |
| 10 | 93982 |
| 11 | 369633 |
| 12 | 1481709 |
| 13 | 5983590 |
| 14 | 24232012 |
| 15 | 99222087 |
| 16 | 407426130 |
| 17 | 1680897964 |
| 18 | 6975369570 |
| 19 | 29010771057 |
| 20 | 121164653294 |
| 21 | 507700418550 |
| 22 | 2132120381475 |
| 23 | 8982067396981 |
| 24 | 37920761022042 |
| 25 | 160429930215705 |
| 26 | 680251829388493 |
| 27 | 2889238380694213 |
| 28 | 12293506617026379 |
[1,1,4,10,35,124,430,1647,6183,23789,93982,369633, 1481709,5983590,24232012,99222087,407426130, 1680897964,6975369570,29010771057,121164653294, 507700418550,2132120381475,8982067396981, 37920761022042,160429930215705,680251829388493, 2889238380694213,12293506617026379] |