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| n | a(n) |
|---|---|
| 0 | 3 |
| 1 | 7 |
| 2 | 17 |
| 3 | 42 |
| 4 | 104 |
| 5 | 258 |
| 6 | 641 |
| 7 | 1593 |
| 8 | 3959 |
| 9 | 9840 |
| 10 | 24458 |
| 11 | 60793 |
| 12 | 151108 |
| 13 | 375597 |
| 14 | 933592 |
| 15 | 2320557 |
| 16 | 5768028 |
| 17 | 14337139 |
| 18 | 35636713 |
| 19 | 88579410 |
| 20 | 220174961 |
| 21 | 547271804 |
| 22 | 1360311028 |
| 23 | 3381219496 |
| 24 | 8404434755 |
| 25 | 20890250880 |
| 26 | 51925274519 |
| 27 | 129066622961 |
| 28 | 320810882887 |
[3,7,17,42,104,258,641,1593,3959,9840,24458,60793, 151108,375597,933592,2320557,5768028,14337139, 35636713,88579410,220174961,547271804,1360311028, 3381219496,8404434755,20890250880,51925274519, 129066622961,320810882887] |