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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 9 |
| 5 | 22 |
| 6 | 54 |
| 7 | 134 |
| 8 | 335 |
| 9 | 843 |
| 10 | 2132 |
| 11 | 5409 |
| 12 | 13761 |
| 13 | 35088 |
| 14 | 89638 |
| 15 | 229361 |
| 16 | 587678 |
| 17 | 1507586 |
| 18 | 3871589 |
| 19 | 9952087 |
| 20 | 25604573 |
| 21 | 65927447 |
| 22 | 169875992 |
| 23 | 438016016 |
| 24 | 1130103976 |
| 25 | 2917412699 |
| 26 | 7535482753 |
| 27 | 19473430909 |
| 28 | 50347508572 |
| 29 | 130228143004 |
| 30 | 336985674038 |
[1,1,2,4,9,22,54,134,335,843,2132,5409,13761, 35088,89638,229361,587678,1507586,3871589,9952087, 25604573,65927447,169875992,438016016,1130103976, 2917412699,7535482753,19473430909,50347508572, 130228143004,336985674038] |