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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 24 |
| 5 | 70 |
| 6 | 264 |
| 7 | 871 |
| 8 | 3427 |
| 9 | 12155 |
| 10 | 49471 |
| 11 | 184280 |
| 12 | 766809 |
| 13 | 2960544 |
| 14 | 12533294 |
| 15 | 49710976 |
| 16 | 213269188 |
| 17 | 864022759 |
| 18 | 3746852106 |
| 19 | 15440886655 |
| 20 | 67553784034 |
| 21 | 282328209955 |
| 22 | 1244366623559 |
| 23 | 5262103516706 |
| 24 | 23339496398318 |
| 25 | 99687654498177 |
| 26 | 444564154370691 |
| 27 | 1915211250088611 |
| 28 | 8581594213513618 |
[1,1,3,7,24,70,264,871,3427,12155,49471,184280, 766809,2960544,12533294,49710976,213269188, 864022759,3746852106,15440886655,67553784034, 282328209955,1244366623559,5262103516706, 23339496398318,99687654498177,444564154370691, 1915211250088611,8581594213513618] |