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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 4 |
| 4 | 13 |
| 5 | 43 |
| 6 | 124 |
| 7 | 388 |
| 8 | 1117 |
| 9 | 3370 |
| 10 | 9967 |
| 11 | 29860 |
| 12 | 88909 |
| 13 | 266896 |
| 14 | 798337 |
| 15 | 2394553 |
| 16 | 7178233 |
| 17 | 21533029 |
| 18 | 64579750 |
| 19 | 193738672 |
| 20 | 581159161 |
| 21 | 1743472426 |
| 22 | 5230263235 |
| 23 | 15690765067 |
| 24 | 47071824676 |
| 25 | 141215472685 |
| 26 | 423645012649 |
| 27 | 1270934954221 |
| 28 | 3812800839124 |
| 29 | 11438402333398 |
| 30 | 34315194788359 |
[1,1,4,13,43,124,388,1117,3370,9967,29860,88909, 266896,798337,2394553,7178233,21533029,64579750, 193738672,581159161,1743472426,5230263235, 15690765067,47071824676,141215472685,423645012649, 1270934954221,3812800839124,11438402333398, 34315194788359] |