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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 5 |
| 3 | 15 |
| 4 | 49 |
| 5 | 170 |
| 6 | 619 |
| 7 | 2302 |
| 8 | 8723 |
| 9 | 33708 |
| 10 | 132118 |
| 11 | 524213 |
| 12 | 2099108 |
| 13 | 8469819 |
| 14 | 34428721 |
| 15 | 140827947 |
| 16 | 579195024 |
| 17 | 2393319428 |
| 18 | 9930326669 |
| 19 | 41361965397 |
| 20 | 172876964154 |
| 21 | 724796212419 |
| 22 | 3047269940521 |
| 23 | 12844242301182 |
| 24 | 54266727185459 |
| 25 | 229774872053471 |
| 26 | 974848465781183 |
| 27 | 4143560333822301 |
[1,2,5,15,49,170,619,2302,8723,33708,132118, 524213,2099108,8469819,34428721,140827947, 579195024,2393319428,9930326669,41361965397, 172876964154,724796212419,3047269940521, 12844242301182,54266727185459,229774872053471, 974848465781183,4143560333822301] |