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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 15 |
| 4 | 37 |
| 5 | 84 |
| 6 | 187 |
| 7 | 421 |
| 8 | 914 |
| 9 | 2001 |
| 10 | 4283 |
| 11 | 9184 |
| 12 | 19611 |
| 13 | 41604 |
| 14 | 87993 |
| 15 | 185387 |
| 16 | 389954 |
| 17 | 817053 |
| 18 | 1709640 |
| 19 | 3567978 |
| 20 | 7433670 |
| 21 | 15460810 |
| 22 | 32103728 |
| 23 | 66567488 |
| 24 | 137840687 |
| 25 | 285076323 |
| 26 | 588891185 |
| 27 | 1215204568 |
| 28 | 2505088087 |
| 29 | 5159284087 |
[1,2,7,15,37,84,187,421,914,2001,4283,9184,19611, 41604,87993,185387,389954,817053,1709640,3567978, 7433670,15460810,32103728,66567488,137840687, 285076323,588891185,1215204568,2505088087, 5159284087] |