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| n | a(n) |
|---|---|
| 1 | 512 |
| 2 | 1544 |
| 3 | 4724 |
| 4 | 15604 |
| 5 | 51144 |
| 6 | 176104 |
| 7 | 597712 |
| 8 | 2109748 |
| 9 | 7324940 |
| 10 | 26321996 |
| 11 | 92931536 |
| 12 | 338626216 |
| 13 | 1211027400 |
| 14 | 4461593140 |
| 15 | 16115753860 |
| 16 | 59891994316 |
| 17 | 218009580968 |
| 18 | 815799341144 |
| 19 | 2987272973648 |
| 20 | 11239524639028 |
| 21 | 41346560068716 |
[512,1544,4724,15604,51144,176104,597712,2109748, 7324940,26321996,92931536,338626216,1211027400, 4461593140,16115753860,59891994316,218009580968, 815799341144,2987272973648,11239524639028, 41346560068716] |