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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 4 |
| 4 | 9 |
| 5 | 40 |
| 6 | 169 |
| 7 | 1054 |
| 8 | 4385 |
| 9 | 9824 |
| 10 | 43681 |
| 11 | 271910 |
| 12 | 587501 |
| 13 | 2621914 |
| 14 | 16318985 |
| 15 | 67897854 |
| 16 | 287910401 |
| 17 | 643718656 |
| 18 | 2862785025 |
| 19 | 17820428806 |
| 20 | 38503642637 |
| 21 | 171834999354 |
| 22 | 725843640053 |
| 23 | 4526896839672 |
| 24 | 18833430998741 |
| 25 | 42193758837154 |
[0,1,4,9,40,169,1054,4385,9824,43681,271910, 587501,2621914,16318985,67897854,287910401, 643718656,2862785025,17820428806,38503642637, 171834999354,725843640053,4526896839672, 18833430998741,42193758837154] |