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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 11 |
| 4 | 46 |
| 5 | 145 |
| 6 | 641 |
| 7 | 2287 |
| 8 | 10362 |
| 9 | 38721 |
| 10 | 178975 |
| 11 | 700051 |
| 12 | 3274170 |
| 13 | 13103091 |
| 14 | 61899718 |
| 15 | 253721395 |
| 16 | 1206633562 |
| 17 | 5014531143 |
| 18 | 23988956031 |
| 19 | 101185506495 |
| 20 | 486117617820 |
| 21 | 2069555088623 |
| 22 | 9981081442588 |
| 23 | 42926937379591 |
| 24 | 207632770875770 |
| 25 | 898992509896095 |
| 26 | 4360150991226725 |
| 27 | 19018904672979927 |
[1,1,4,11,46,145,641,2287,10362,38721,178975, 700051,3274170,13103091,61899718,253721395, 1206633562,5014531143,23988956031,101185506495, 486117617820,2069555088623,9981081442588, 42926937379591,207632770875770,898992509896095, 4360150991226725,19018904672979927] |