| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 5 |
| 2 | 28 |
| 3 | 189 |
| 4 | 1232 |
| 5 | 7651 |
| 6 | 46440 |
| 7 | 279593 |
| 8 | 1679104 |
| 9 | 10076967 |
| 10 | 60465176 |
| 11 | 362795725 |
| 12 | 2176780608 |
| 13 | 13060691819 |
| 14 | 78364161352 |
| 15 | 470184981201 |
| 16 | 2821109903360 |
| 17 | 16926659439823 |
| 18 | 101559956662584 |
| 19 | 609359740003637 |
[1,5,28,189,1232,7651,46440,279593,1679104, 10076967,60465176,362795725,2176780608, 13060691819,78364161352,470184981201, 2821109903360,16926659439823,101559956662584, 609359740003637] |