| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 9 |
| 3 | 26 |
| 4 | 72 |
| 5 | 194 |
| 6 | 515 |
| 7 | 1357 |
| 8 | 3563 |
| 9 | 9340 |
| 10 | 24466 |
| 11 | 64068 |
| 12 | 167749 |
| 13 | 439191 |
| 14 | 1149837 |
| 15 | 3010334 |
| 16 | 7881180 |
| 17 | 20633222 |
| 18 | 54018503 |
| 19 | 141422305 |
| 20 | 370248431 |
| 21 | 969323008 |
| 22 | 2537720614 |
| 23 | 6643838856 |
| 24 | 17393795977 |
| 25 | 45537549099 |
| 26 | 119218851345 |
[1,3,9,26,72,194,515,1357,3563,9340,24466,64068, 167749,439191,1149837,3010334,7881180,20633222, 54018503,141422305,370248431,969323008,2537720614, 6643838856,17393795977,45537549099,119218851345] |