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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 13 |
| 5 | 34 |
| 6 | 116 |
| 7 | 330 |
| 8 | 1162 |
| 9 | 3536 |
| 10 | 12877 |
| 11 | 41066 |
| 12 | 151769 |
| 13 | 498166 |
| 14 | 1860262 |
| 15 | 6254556 |
| 16 | 23590016 |
| 17 | 80834615 |
| 18 | 306837983 |
| 19 | 1066600624 |
| 20 | 4068927054 |
| 21 | 14319207670 |
| 22 | 54880379628 |
| 23 | 195141810984 |
| 24 | 750525883409 |
| 25 | 2691555567339 |
| 26 | 10382014415381 |
| 27 | 37512878118392 |
| 28 | 145085352407058 |
| 29 | 527672333478588 |
| 30 | 2045307592522895 |
[1,1,2,4,13,34,116,330,1162,3536,12877,41066, 151769,498166,1860262,6254556,23590016,80834615, 306837983,1066600624,4068927054,14319207670, 54880379628,195141810984,750525883409, 2691555567339,10382014415381,37512878118392, 145085352407058,527672333478588,2045307592522895] |