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| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 8 |
| 3 | 25 |
| 4 | 68 |
| 5 | 177 |
| 6 | 457 |
| 7 | 1183 |
| 8 | 3075 |
| 9 | 8018 |
| 10 | 20947 |
| 11 | 54782 |
| 12 | 143348 |
| 13 | 375200 |
| 14 | 982178 |
| 15 | 2571247 |
| 16 | 6731462 |
| 17 | 17623023 |
| 18 | 46137475 |
| 19 | 120789253 |
| 20 | 316230117 |
| 21 | 827900912 |
| 22 | 2167472413 |
| 23 | 5674516100 |
| 24 | 14856075638 |
| 25 | 38893710542 |
| 26 | 101825055692 |
| 27 | 266581456213 |
[2,8,25,68,177,457,1183,3075,8018,20947,54782, 143348,375200,982178,2571247,6731462,17623023, 46137475,120789253,316230117,827900912,2167472413, 5674516100,14856075638,38893710542,101825055692, 266581456213] |