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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 10 |
| 5 | 22 |
| 6 | 62 |
| 7 | 146 |
| 8 | 420 |
| 9 | 1050 |
| 10 | 3124 |
| 11 | 7956 |
| 12 | 23957 |
| 13 | 62486 |
| 14 | 192129 |
| 15 | 509457 |
| 16 | 1560782 |
| 17 | 4196095 |
| 18 | 13066095 |
| 19 | 35437076 |
| 20 | 109838408 |
| 21 | 301261013 |
| 22 | 944939968 |
| 23 | 2605796828 |
| 24 | 8124857765 |
| 25 | 22597326279 |
| 26 | 71095025143 |
| 27 | 198583977503 |
[1,1,2,4,10,22,62,146,420,1050,3124,7956,23957, 62486,192129,509457,1560782,4196095,13066095, 35437076,109838408,301261013,944939968,2605796828, 8124857765,22597326279,71095025143,198583977503] |