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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 6 |
| 3 | 36 |
| 4 | 186 |
| 5 | 1254 |
| 6 | 8208 |
| 7 | 57540 |
| 8 | 404619 |
| 9 | 2913705 |
| 10 | 21146694 |
| 11 | 155231256 |
| 12 | 1147302756 |
| 13 | 8538393900 |
| 14 | 63879354096 |
| 15 | 480212156664 |
| 16 | 3624581868297 |
| 17 | 27456690186507 |
| 18 | 208644709097070 |
| 19 | 1589982296208492 |
| 20 | 12147079485362406 |
| 21 | 93012131704072698 |
| 22 | 713676733469348352 |
[1,3,6,36,186,1254,8208,57540,404619,2913705, 21146694,155231256,1147302756,8538393900, 63879354096,480212156664,3624581868297, 27456690186507,208644709097070,1589982296208492, 12147079485362406,93012131704072698, 713676733469348352] |