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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 1 |
| 3 | 0 |
| 4 | 1 |
| 5 | 1 |
| 6 | 3 |
| 7 | 3 |
| 8 | 9 |
| 9 | 15 |
| 10 | 38 |
| 11 | 73 |
| 12 | 174 |
| 13 | 380 |
| 14 | 915 |
| 15 | 2124 |
| 16 | 5134 |
| 17 | 12281 |
| 18 | 30010 |
| 19 | 73401 |
| 20 | 181835 |
| 21 | 452165 |
| 22 | 1133252 |
| 23 | 2851710 |
| 24 | 7215262 |
| 25 | 18326528 |
| 26 | 46750268 |
| 27 | 119687146 |
| 28 | 307528889 |
| 29 | 792716193 |
| 30 | 2049703887 |
| 31 | 5314775856 |
| 32 | 13817638615 |
| 33 | 36012395538 |
[0,0,1,0,1,1,3,3,9,15,38,73,174,380,915,2124,5134, 12281,30010,73401,181835,452165,1133252,2851710, 7215262,18326528,46750268,119687146,307528889, 792716193,2049703887,5314775856,13817638615, 36012395538] |