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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 4 |
| 3 | 9 |
| 4 | 18 |
| 5 | 40 |
| 6 | 80 |
| 7 | 175 |
| 8 | 350 |
| 9 | 756 |
| 10 | 1512 |
| 11 | 3234 |
| 12 | 6468 |
| 13 | 13728 |
| 14 | 27456 |
| 15 | 57915 |
| 16 | 115830 |
| 17 | 243100 |
| 18 | 486200 |
| 19 | 1016158 |
| 20 | 2032316 |
| 21 | 4232592 |
| 22 | 8465184 |
| 23 | 17577014 |
| 24 | 35154028 |
| 25 | 72804200 |
| 26 | 145608400 |
| 27 | 300874500 |
| 28 | 601749000 |
| 29 | 1240940160 |
| 30 | 2481880320 |
| 31 | 5109183315 |
| 32 | 10218366630 |
[1,2,4,9,18,40,80,175,350,756,1512,3234,6468, 13728,27456,57915,115830,243100,486200,1016158, 2032316,4232592,8465184,17577014,35154028, 72804200,145608400,300874500,601749000,1240940160, 2481880320,5109183315,10218366630] |