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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 7 |
| 3 | 24 |
| 4 | 82 |
| 5 | 280 |
| 6 | 956 |
| 7 | 3264 |
| 8 | 11144 |
| 9 | 38048 |
| 10 | 129904 |
| 11 | 443520 |
| 12 | 1514272 |
| 13 | 5170048 |
| 14 | 17651648 |
| 15 | 60266496 |
| 16 | 205762688 |
| 17 | 702517760 |
| 18 | 2398545664 |
| 19 | 8189147136 |
| 20 | 27959497216 |
| 21 | 95459694592 |
| 22 | 325919783936 |
| 23 | 1112759746560 |
| 24 | 3799199418368 |
| 25 | 12971278180352 |
| 26 | 44286713884672 |
| 27 | 151204299177984 |
[1,2,7,24,82,280,956,3264,11144,38048,129904, 443520,1514272,5170048,17651648,60266496, 205762688,702517760,2398545664,8189147136, 27959497216,95459694592,325919783936, 1112759746560,3799199418368,12971278180352, 44286713884672,151204299177984] |