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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 1 |
| 3 | 3 |
| 4 | 10 |
| 5 | 28 |
| 6 | 77 |
| 7 | 203 |
| 8 | 526 |
| 9 | 1340 |
| 10 | 3377 |
| 11 | 8435 |
| 12 | 20930 |
| 13 | 51660 |
| 14 | 126981 |
| 15 | 311083 |
| 16 | 760070 |
| 17 | 1853068 |
| 18 | 4509897 |
| 19 | 10960243 |
| 20 | 26605146 |
| 21 | 64520060 |
| 22 | 156344317 |
| 23 | 378606795 |
| 24 | 916354110 |
| 25 | 2216907420 |
| 26 | 5361353761 |
| 27 | 12961984563 |
| 28 | 31330062130 |
| 29 | 75711587308 |
| 30 | 182932193717 |
[0,0,1,3,10,28,77,203,526,1340,3377,8435,20930, 51660,126981,311083,760070,1853068,4509897, 10960243,26605146,64520060,156344317,378606795, 916354110,2216907420,5361353761,12961984563, 31330062130,75711587308,182932193717] |