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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 17 |
| 5 | 40 |
| 6 | 98 |
| 7 | 233 |
| 8 | 562 |
| 9 | 1349 |
| 10 | 3243 |
| 11 | 7789 |
| 12 | 18722 |
| 13 | 44978 |
| 14 | 108083 |
| 15 | 259700 |
| 16 | 624027 |
| 17 | 1499427 |
| 18 | 3602913 |
| 19 | 8657216 |
| 20 | 20801982 |
| 21 | 49983920 |
| 22 | 120103675 |
| 23 | 288590527 |
| 24 | 693438537 |
| 25 | 1666225599 |
| 26 | 4003682857 |
| 27 | 9620231375 |
| 28 | 23115930197 |
| 29 | 55544009564 |
[1,1,3,7,17,40,98,233,562,1349,3243,7789,18722, 44978,108083,259700,624027,1499427,3602913, 8657216,20801982,49983920,120103675,288590527, 693438537,1666225599,4003682857,9620231375, 23115930197,55544009564] |