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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 21 |
| 5 | 73 |
| 6 | 239 |
| 7 | 736 |
| 8 | 2158 |
| 9 | 6102 |
| 10 | 16813 |
| 11 | 45493 |
| 12 | 121567 |
| 13 | 322108 |
| 14 | 848654 |
| 15 | 2227722 |
| 16 | 5834253 |
| 17 | 15258361 |
| 18 | 39874967 |
| 19 | 104169568 |
| 20 | 272109046 |
| 21 | 710846406 |
| 22 | 1857283957 |
| 23 | 4853664901 |
| 24 | 12686932951 |
| 25 | 33169384588 |
| 26 | 86737334054 |
| 27 | 226858067466 |
| 28 | 593434214373 |
| 29 | 1552572159577 |
| 30 | 4062403215263 |
| 31 | 10630610953408 |
[1,1,2,6,21,73,239,736,2158,6102,16813,45493, 121567,322108,848654,2227722,5834253,15258361, 39874967,104169568,272109046,710846406,1857283957, 4853664901,12686932951,33169384588,86737334054, 226858067466,593434214373,1552572159577, 4062403215263,10630610953408] |