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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 3 |
| 4 | 16 |
| 5 | 65 |
| 6 | 238 |
| 7 | 866 |
| 8 | 3128 |
| 9 | 11493 |
| 10 | 42660 |
| 11 | 160584 |
| 12 | 610640 |
| 13 | 2345504 |
| 14 | 9081768 |
| 15 | 35422175 |
| 16 | 139022622 |
| 17 | 548671517 |
| 18 | 2176051050 |
| 19 | 8668363573 |
| 20 | 34667284390 |
| 21 | 139140830956 |
| 22 | 560271494630 |
| 23 | 2262709876003 |
| 24 | 9163000968554 |
| 25 | 37198940600264 |
| 26 | 151364381618576 |
[0,0,3,16,65,238,866,3128,11493,42660,160584, 610640,2345504,9081768,35422175,139022622, 548671517,2176051050,8668363573,34667284390, 139140830956,560271494630,2262709876003, 9163000968554,37198940600264,151364381618576] |