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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 3 |
| 3 | 7 |
| 4 | 17 |
| 5 | 40 |
| 6 | 93 |
| 7 | 216 |
| 8 | 502 |
| 9 | 1167 |
| 10 | 2713 |
| 11 | 6307 |
| 12 | 14662 |
| 13 | 34085 |
| 14 | 79238 |
| 15 | 184206 |
| 16 | 428227 |
| 17 | 995507 |
| 18 | 2314273 |
| 19 | 5380032 |
| 20 | 12507057 |
| 21 | 29075380 |
| 22 | 67592058 |
| 23 | 157132471 |
| 24 | 365288677 |
| 25 | 849193147 |
| 26 | 1974134558 |
| 27 | 4589306057 |
| 28 | 10668842202 |
[1,2,3,7,17,40,93,216,502,1167,2713,6307,14662, 34085,79238,184206,428227,995507,2314273,5380032, 12507057,29075380,67592058,157132471,365288677, 849193147,1974134558,4589306057,10668842202] |