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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 2 |
| 3 | 6 |
| 4 | 15 |
| 5 | 32 |
| 6 | 79 |
| 7 | 172 |
| 8 | 397 |
| 9 | 860 |
| 10 | 1879 |
| 11 | 3986 |
| 12 | 8462 |
| 13 | 17586 |
| 14 | 36408 |
| 15 | 74366 |
| 16 | 150875 |
| 17 | 303006 |
| 18 | 604511 |
| 19 | 1195872 |
| 20 | 2350614 |
| 21 | 4587484 |
| 22 | 8898857 |
| 23 | 17154278 |
| 24 | 32883109 |
| 25 | 62679852 |
| 26 | 118858190 |
| 27 | 224238730 |
| 28 | 421021209 |
| 29 | 786793776 |
| 30 | 1463796383 |
| 31 | 2711552690 |
| 32 | 5002097398 |
| 33 | 9190449808 |
[1,0,2,6,15,32,79,172,397,860,1879,3986,8462, 17586,36408,74366,150875,303006,604511,1195872, 2350614,4587484,8898857,17154278,32883109, 62679852,118858190,224238730,421021209,786793776, 1463796383,2711552690,5002097398,9190449808] |