| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 4 |
| 3 | 13 |
| 4 | 26 |
| 5 | 100 |
| 6 | 196 |
| 7 | 820 |
| 8 | 1581 |
| 9 | 6954 |
| 10 | 13244 |
| 11 | 60214 |
| 12 | 113620 |
| 13 | 528840 |
| 14 | 990756 |
| 15 | 4692780 |
| 16 | 8741876 |
| 17 | 41970280 |
| 18 | 77824912 |
| 19 | 377687453 |
| 20 | 697689538 |
| 21 | 3415756084 |
| 22 | 6289798684 |
| 23 | 31018849628 |
| 24 | 56964451670 |
| 25 | 282658474700 |
| 26 | 517885177320 |
[1,2,4,13,26,100,196,820,1581,6954,13244,60214, 113620,528840,990756,4692780,8741876,41970280, 77824912,377687453,697689538,3415756084, 6289798684,31018849628,56964451670,282658474700, 517885177320] |