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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 60 |
| 7 | 455 |
| 8 | 2268 |
| 9 | 9366 |
| 10 | 34800 |
| 11 | 121077 |
| 12 | 403392 |
| 13 | 1304732 |
| 14 | 4133220 |
| 15 | 12900771 |
| 16 | 39837684 |
| 17 | 122064930 |
| 18 | 371891592 |
| 19 | 1128317489 |
| 20 | 3412864056 |
| 21 | 10299925992 |
| 22 | 31033986588 |
| 23 | 93394501983 |
| 24 | 280818931020 |
| 25 | 843832511150 |
| 26 | 2534467085280 |
| 27 | 7609793357805 |
| 28 | 22843103816688 |
| 29 | 68558705110836 |
[0,0,0,0,0,0,60,455,2268,9366,34800,121077,403392, 1304732,4133220,12900771,39837684,122064930, 371891592,1128317489,3412864056,10299925992, 31033986588,93394501983,280818931020,843832511150, 2534467085280,7609793357805,22843103816688, 68558705110836] |