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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 27 |
| 2 | 324 |
| 3 | 2430 |
| 4 | 13716 |
| 5 | 64557 |
| 6 | 265356 |
| 7 | 983556 |
| 8 | 3353076 |
| 9 | 10670373 |
| 10 | 32031288 |
| 11 | 91455804 |
| 12 | 249948828 |
| 13 | 657261999 |
| 14 | 1669898592 |
| 15 | 4113612864 |
| 16 | 9853898292 |
| 17 | 23010586596 |
| 18 | 52494114852 |
| 19 | 117209543940 |
| 20 | 256559365656 |
| 21 | 551320914321 |
| 22 | 1164556135440 |
| 23 | 2420715030912 |
| 24 | 4956677613180 |
[1,27,324,2430,13716,64557,265356,983556,3353076, 10670373,32031288,91455804,249948828,657261999, 1669898592,4113612864,9853898292,23010586596, 52494114852,117209543940,256559365656, 551320914321,1164556135440,2420715030912, 4956677613180] |