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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 4 |
| 4 | 44 |
| 5 | 288 |
| 6 | 1537 |
| 7 | 7328 |
| 8 | 32515 |
| 9 | 137127 |
| 10 | 557042 |
| 11 | 2199406 |
| 12 | 8493667 |
| 13 | 32225692 |
| 14 | 120526196 |
| 15 | 445477330 |
| 16 | 1630344366 |
| 17 | 5917000834 |
| 18 | 21321552087 |
| 19 | 76358216811 |
| 20 | 271995346780 |
| 21 | 964328895552 |
| 22 | 3404784217800 |
| 23 | 11977326096426 |
| 24 | 41996294148654 |
[0,0,4,44,288,1537,7328,32515,137127,557042, 2199406,8493667,32225692,120526196,445477330, 1630344366,5917000834,21321552087,76358216811, 271995346780,964328895552,3404784217800, 11977326096426,41996294148654] |