| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 10 |
| 4 | 28 |
| 5 | 64 |
| 6 | 172 |
| 7 | 388 |
| 8 | 1036 |
| 9 | 2332 |
| 10 | 6220 |
| 11 | 13996 |
| 12 | 37324 |
| 13 | 83980 |
| 14 | 223948 |
| 15 | 503884 |
| 16 | 1343692 |
| 17 | 3023308 |
| 18 | 8062156 |
| 19 | 18139852 |
| 20 | 48372940 |
| 21 | 108839116 |
| 22 | 290237644 |
| 23 | 653034700 |
| 24 | 1741425868 |
| 25 | 3918208204 |
| 26 | 10448555212 |
| 27 | 23509249228 |
| 28 | 62691331276 |
[1,4,10,28,64,172,388,1036,2332,6220,13996,37324, 83980,223948,503884,1343692,3023308,8062156, 18139852,48372940,108839116,290237644,653034700, 1741425868,3918208204,10448555212,23509249228, 62691331276] |