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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 4 |
| 5 | 11 |
| 6 | 15 |
| 7 | 71 |
| 8 | 228 |
| 9 | 3035 |
| 10 | 15403 |
| 11 | 18438 |
| 12 | 33841 |
| 13 | 289166 |
| 14 | 323007 |
| 15 | 935180 |
| 16 | 4063727 |
| 17 | 4998907 |
| 18 | 9062634 |
| 19 | 367504267 |
| 20 | 376566901 |
| 21 | 4509740178 |
| 22 | 13905787435 |
| 23 | 101850252223 |
| 24 | 115756039658 |
| 25 | 912142529829 |
| 26 | 1027898569487 |
| 27 | 1940041099316 |
[0,1,1,3,4,11,15,71,228,3035,15403,18438,33841, 289166,323007,935180,4063727,4998907,9062634, 367504267,376566901,4509740178,13905787435, 101850252223,115756039658,912142529829, 1027898569487,1940041099316] |