| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 23 |
| 3 | 76 |
| 4 | 208 |
| 5 | 519 |
| 6 | 1212 |
| 7 | 2670 |
| 8 | 5574 |
| 9 | 11076 |
| 10 | 21043 |
| 11 | 38390 |
| 12 | 67522 |
| 13 | 114907 |
| 14 | 189804 |
| 15 | 305172 |
| 16 | 478788 |
| 17 | 734604 |
| 18 | 1104375 |
| 19 | 1629592 |
| 20 | 2363756 |
| 21 | 3375031 |
| 22 | 4749316 |
| 23 | 6593778 |
| 24 | 9040890 |
| 25 | 12253020 |
| 26 | 16427619 |
| 27 | 21803058 |
| 28 | 28665166 |
| 29 | 37354523 |
| 30 | 48274564 |
| 31 | 61900552 |
[4,23,76,208,519,1212,2670,5574,11076,21043,38390, 67522,114907,189804,305172,478788,734604,1104375, 1629592,2363756,3375031,4749316,6593778,9040890, 12253020,16427619,21803058,28665166,37354523, 48274564,61900552] |