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| n | a(n) |
|---|---|
| 1 | 81 |
| 2 | 150 |
| 3 | 537 |
| 4 | 2052 |
| 5 | 7878 |
| 6 | 29760 |
| 7 | 112236 |
| 8 | 423288 |
| 9 | 1596672 |
| 10 | 6022920 |
| 11 | 22719480 |
| 12 | 85701576 |
| 13 | 323280168 |
| 14 | 1219464936 |
| 15 | 4600018536 |
| 16 | 17352012360 |
| 17 | 65454591240 |
| 18 | 246905282472 |
| 19 | 931366575720 |
| 20 | 3513265045128 |
| 21 | 13252602787272 |
| 22 | 49990956668904 |
[81,150,537,2052,7878,29760,112236,423288,1596672, 6022920,22719480,85701576,323280168,1219464936, 4600018536,17352012360,65454591240,246905282472, 931366575720,3513265045128,13252602787272, 49990956668904] |