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| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 9 |
| 3 | 21 |
| 4 | 51 |
| 5 | 127 |
| 6 | 324 |
| 7 | 844 |
| 8 | 2243 |
| 9 | 6073 |
| 10 | 16736 |
| 11 | 46892 |
| 12 | 133443 |
| 13 | 385277 |
| 14 | 1127352 |
| 15 | 3339464 |
| 16 | 10003395 |
| 17 | 30269129 |
| 18 | 92422160 |
| 19 | 284470820 |
| 20 | 881804563 |
| 21 | 2750412037 |
| 22 | 8625112792 |
| 23 | 27174303856 |
| 24 | 85960269683 |
| 25 | 272856760081 |
| 26 | 868664396112 |
[4,9,21,51,127,324,844,2243,6073,16736,46892, 133443,385277,1127352,3339464,10003395,30269129, 92422160,284470820,881804563,2750412037, 8625112792,27174303856,85960269683,272856760081, 868664396112] |