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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 9 |
| 4 | 34 |
| 5 | 94 |
| 6 | 368 |
| 7 | 1131 |
| 8 | 4466 |
| 9 | 14468 |
| 10 | 57356 |
| 11 | 193200 |
| 12 | 767664 |
| 13 | 2650814 |
| 14 | 10552660 |
| 15 | 37141229 |
| 16 | 148040634 |
| 17 | 528844796 |
| 18 | 2109494072 |
| 19 | 7623040680 |
| 20 | 30426290940 |
| 21 | 110998813606 |
| 22 | 443245452212 |
| 23 | 1629794707352 |
| 24 | 6510278089072 |
| 25 | 24096191513060 |
| 26 | 96278729708172 |
| 27 | 358370832690704 |
| 28 | 1432209340089340 |
| 29 | 5357082370310378 |
[1,1,4,9,34,94,368,1131,4466,14468,57356,193200, 767664,2650814,10552660,37141229,148040634, 528844796,2109494072,7623040680,30426290940, 110998813606,443245452212,1629794707352, 6510278089072,24096191513060,96278729708172, 358370832690704,1432209340089340,5357082370310378] |