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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 5 |
| 3 | 10 |
| 4 | 20 |
| 5 | 43 |
| 6 | 90 |
| 7 | 190 |
| 8 | 400 |
| 9 | 846 |
| 10 | 1789 |
| 11 | 3783 |
| 12 | 8000 |
| 13 | 16918 |
| 14 | 35778 |
| 15 | 75660 |
| 16 | 160000 |
| 17 | 338359 |
| 18 | 715542 |
| 19 | 1513187 |
| 20 | 3200000 |
| 21 | 6767177 |
| 22 | 14310836 |
| 23 | 30263732 |
| 24 | 64000000 |
| 25 | 135343522 |
| 26 | 286216702 |
| 27 | 605274630 |
| 28 | 1280000000 |
[1,3,5,10,20,43,90,190,400,846,1789,3783,8000, 16918,35778,75660,160000,338359,715542,1513187, 3200000,6767177,14310836,30263732,64000000, 135343522,286216702,605274630,1280000000] |