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| n | a(n) |
|---|---|
| 0 | 3 |
| 1 | 27 |
| 2 | 125 |
| 3 | 420 |
| 4 | 1161 |
| 5 | 2807 |
| 6 | 6147 |
| 7 | 12465 |
| 8 | 23760 |
| 9 | 43032 |
| 10 | 74646 |
| 11 | 124787 |
| 12 | 202020 |
| 13 | 317970 |
| 14 | 488138 |
| 15 | 732870 |
| 16 | 1078497 |
| 17 | 1558665 |
| 18 | 2215875 |
| 19 | 3103254 |
| 20 | 4286579 |
| 21 | 5846577 |
| 22 | 7881525 |
| 23 | 10510175 |
| 24 | 13875030 |
| 25 | 18145998 |
| 26 | 23524452 |
[3,27,125,420,1161,2807,6147,12465,23760,43032, 74646,124787,202020,317970,488138,732870,1078497, 1558665,2215875,3103254,4286579,5846577,7881525, 10510175,13875030,18145998,23524452] |