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| n | a(n) |
|---|---|
| 0 | 2 |
| 1 | 7 |
| 2 | 22 |
| 3 | 67 |
| 4 | 200 |
| 5 | 588 |
| 6 | 1708 |
| 7 | 4913 |
| 8 | 14018 |
| 9 | 39725 |
| 10 | 111922 |
| 11 | 313752 |
| 12 | 875702 |
| 13 | 2434747 |
| 14 | 6746350 |
| 15 | 18636343 |
| 16 | 51340988 |
| 17 | 141089508 |
| 18 | 386857888 |
| 19 | 1058572325 |
| 20 | 2891193242 |
| 21 | 7882921697 |
| 22 | 21458980582 |
| 23 | 58330331952 |
| 24 | 158339542250 |
| 25 | 429274563823 |
| 26 | 1162435429318 |
| 27 | 3144299295403 |
[2,7,22,67,200,588,1708,4913,14018,39725,111922, 313752,875702,2434747,6746350,18636343,51340988, 141089508,386857888,1058572325,2891193242, 7882921697,21458980582,58330331952,158339542250, 429274563823,1162435429318,3144299295403] |