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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 4 |
| 5 | 9 |
| 6 | 20 |
| 7 | 47 |
| 8 | 113 |
| 9 | 281 |
| 10 | 706 |
| 11 | 1807 |
| 12 | 4671 |
| 13 | 12223 |
| 14 | 32245 |
| 15 | 85777 |
| 16 | 229670 |
| 17 | 618732 |
| 18 | 1675523 |
| 19 | 4558995 |
| 20 | 12456746 |
| 21 | 34166520 |
| 22 | 94034681 |
| 23 | 259621349 |
| 24 | 718846409 |
| 25 | 1995609079 |
| 26 | 5553497132 |
| 27 | 15489246752 |
| 28 | 43290735944 |
| 29 | 121226413303 |
| 30 | 340079037154 |
| 31 | 955633681302 |
[0,1,1,2,4,9,20,47,113,281,706,1807,4671,12223, 32245,85777,229670,618732,1675523,4558995, 12456746,34166520,94034681,259621349,718846409, 1995609079,5553497132,15489246752,43290735944, 121226413303,340079037154,955633681302] |