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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 1 |
| 3 | 1 |
| 4 | 2 |
| 5 | 2 |
| 6 | 4 |
| 7 | 8 |
| 8 | 9 |
| 9 | 13 |
| 10 | 28 |
| 11 | 40 |
| 12 | 68 |
| 13 | 188 |
| 14 | 247 |
| 15 | 498 |
| 16 | 1534 |
| 17 | 2240 |
| 18 | 5457 |
| 19 | 19030 |
| 20 | 34984 |
| 21 | 92787 |
| 22 | 351730 |
| 23 | 736460 |
| 24 | 2179274 |
| 25 | 9660082 |
| 26 | 22277066 |
| 27 | 75466794 |
| 28 | 381461162 |
| 29 | 984019235 |
| 30 | 3823360536 |
[1,2,1,1,2,2,4,8,9,13,28,40,68,188,247,498,1534, 2240,5457,19030,34984,92787,351730,736460,2179274, 9660082,22277066,75466794,381461162,984019235, 3823360536] |