| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 7 |
| 5 | 25 |
| 6 | 61 |
| 7 | 121 |
| 8 | 283 |
| 9 | 841 |
| 10 | 2521 |
| 11 | 6769 |
| 12 | 17119 |
| 13 | 44665 |
| 14 | 123685 |
| 15 | 347497 |
| 16 | 954787 |
| 17 | 2578297 |
| 18 | 7001617 |
| 19 | 19307089 |
| 20 | 53601175 |
| 21 | 148305817 |
| 22 | 408681997 |
| 23 | 1127558041 |
| 24 | 3124344427 |
| 25 | 8681565865 |
| 26 | 24127128841 |
| 27 | 67020060721 |
| 28 | 186282015823 |
[1,1,1,1,7,25,61,121,283,841,2521,6769,17119, 44665,123685,347497,954787,2578297,7001617, 19307089,53601175,148305817,408681997,1127558041, 3124344427,8681565865,24127128841,67020060721, 186282015823] |