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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 11 |
| 3 | 37 |
| 4 | 121 |
| 5 | 402 |
| 6 | 1331 |
| 7 | 4415 |
| 8 | 14641 |
| 9 | 48559 |
| 10 | 161051 |
| 11 | 534146 |
| 12 | 1771561 |
| 13 | 5875604 |
| 14 | 19487171 |
| 15 | 64631635 |
| 16 | 214358881 |
| 17 | 710947979 |
| 18 | 2357947691 |
| 19 | 7820427767 |
| 20 | 25937424601 |
| 21 | 86024705430 |
| 22 | 285311670611 |
[1,4,11,37,121,402,1331,4415,14641,48559,161051, 534146,1771561,5875604,19487171,64631635, 214358881,710947979,2357947691,7820427767, 25937424601,86024705430,285311670611] |