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| n | a(n) |
|---|---|
| 3 | 1 |
| 4 | 9 |
| 5 | 45 |
| 6 | 174 |
| 7 | 576 |
| 8 | 1719 |
| 9 | 4761 |
| 10 | 12441 |
| 11 | 31050 |
| 12 | 74593 |
| 13 | 173547 |
| 14 | 392787 |
| 15 | 867876 |
| 16 | 1877322 |
| 17 | 3984636 |
| 18 | 8314434 |
| 19 | 17082510 |
| 20 | 34604523 |
| 21 | 69194309 |
| 22 | 136709688 |
| 23 | 267111510 |
| 24 | 516515227 |
| 25 | 989147760 |
| 26 | 1877103486 |
| 27 | 3531796959 |
| 28 | 6591644601 |
| 29 | 12208734552 |
| 30 | 22449066710 |
| 31 | 40995144288 |
[1,9,45,174,576,1719,4761,12441,31050,74593, 173547,392787,867876,1877322,3984636,8314434, 17082510,34604523,69194309,136709688,267111510, 516515227,989147760,1877103486,3531796959, 6591644601,12208734552,22449066710,40995144288] |