| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 4 |
| 3 | 8 |
| 4 | 22 |
| 5 | 46 |
| 6 | 128 |
| 7 | 268 |
| 8 | 746 |
| 9 | 1562 |
| 10 | 4348 |
| 11 | 9104 |
| 12 | 25342 |
| 13 | 53062 |
| 14 | 147704 |
| 15 | 309268 |
| 16 | 860882 |
| 17 | 1802546 |
| 18 | 5017588 |
| 19 | 10506008 |
| 20 | 29244646 |
| 21 | 61233502 |
| 22 | 170450288 |
| 23 | 356895004 |
| 24 | 993457082 |
| 25 | 2080136522 |
| 26 | 5790292204 |
| 27 | 12123924128 |
| 28 | 33748296142 |
| 29 | 70663408246 |
| 30 | 196699484648 |
[2,4,8,22,46,128,268,746,1562,4348,9104,25342, 53062,147704,309268,860882,1802546,5017588, 10506008,29244646,61233502,170450288,356895004, 993457082,2080136522,5790292204,12123924128, 33748296142,70663408246,196699484648] |