| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 14 |
| 3 | 106 |
| 4 | 784 |
| 5 | 6040 |
| 6 | 47332 |
| 7 | 375196 |
| 8 | 3001966 |
| 9 | 24190148 |
| 10 | 196034522 |
| 11 | 1596030740 |
| 12 | 13044459766 |
| 13 | 106961525744 |
| 14 | 879512777006 |
| 15 | 7249483605580 |
| 16 | 59881171431050 |
| 17 | 495545064567260 |
| 18 | 4107666916668414 |
| 19 | 34099685718629264 |
| 20 | 283454909832384416 |
| 21 | 2359069189033880228 |
[1,2,14,106,784,6040,47332,375196,3001966, 24190148,196034522,1596030740,13044459766, 106961525744,879512777006,7249483605580, 59881171431050,495545064567260,4107666916668414, 34099685718629264,283454909832384416, 2359069189033880228] |