| n | a(n) |
|---|---|
| 1 | 28 |
| 2 | 222 |
| 3 | 954 |
| 4 | 2956 |
| 5 | 7440 |
| 6 | 16218 |
| 7 | 31822 |
| 8 | 57624 |
| 9 | 97956 |
| 10 | 158230 |
| 11 | 245058 |
| 12 | 366372 |
| 13 | 531544 |
| 14 | 751506 |
| 15 | 1038870 |
| 16 | 1408048 |
| 17 | 1875372 |
| 18 | 2459214 |
| 19 | 3180106 |
| 20 | 4060860 |
| 21 | 5126688 |
| 22 | 6405322 |
| 23 | 7927134 |
| 24 | 9725256 |
| 25 | 11835700 |
| 26 | 14297478 |
| 27 | 17152722 |
| 28 | 20446804 |
| 29 | 24228456 |
[28,222,954,2956,7440,16218,31822,57624,97956, 158230,245058,366372,531544,751506,1038870, 1408048,1875372,2459214,3180106,4060860,5126688, 6405322,7927134,9725256,11835700,14297478, 17152722,20446804,24228456] |