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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 14 |
| 3 | 99 |
| 4 | 540 |
| 5 | 2565 |
| 6 | 11178 |
| 7 | 45927 |
| 8 | 180792 |
| 9 | 688905 |
| 10 | 2558790 |
| 11 | 9310059 |
| 12 | 33303636 |
| 13 | 117448461 |
| 14 | 409209570 |
| 15 | 1410975855 |
| 16 | 4821232752 |
| 17 | 16343405073 |
| 18 | 55013709438 |
| 19 | 184024732275 |
| 20 | 612124372620 |
| 21 | 2025821736981 |
| 22 | 6673705343514 |
| 23 | 21893519253879 |
| 24 | 71548815908520 |
| 25 | 233004367596825 |
[0,1,14,99,540,2565,11178,45927,180792,688905, 2558790,9310059,33303636,117448461,409209570, 1410975855,4821232752,16343405073,55013709438, 184024732275,612124372620,2025821736981, 6673705343514,21893519253879,71548815908520, 233004367596825] |