| n | a(n) |
|---|---|
| 2 | 3 |
| 3 | 16 |
| 4 | 55 |
| 5 | 156 |
| 6 | 399 |
| 7 | 960 |
| 8 | 2223 |
| 9 | 5020 |
| 10 | 11143 |
| 11 | 24432 |
| 12 | 53079 |
| 13 | 114492 |
| 14 | 245535 |
| 15 | 524032 |
| 16 | 1113823 |
| 17 | 2358972 |
| 18 | 4980375 |
| 19 | 10485360 |
| 20 | 22019655 |
| 21 | 46136860 |
| 22 | 96468463 |
| 23 | 201326016 |
| 24 | 419429775 |
| 25 | 872414556 |
| 26 | 1811938599 |
| 27 | 3758095600 |
| 28 | 7784627383 |
| 29 | 16106126460 |
| 30 | 33285995583 |
| 31 | 68719475712 |
[3,16,55,156,399,960,2223,5020,11143,24432,53079, 114492,245535,524032,1113823,2358972,4980375, 10485360,22019655,46136860,96468463,201326016, 419429775,872414556,1811938599,3758095600, 7784627383,16106126460,33285995583,68719475712] |