| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 19 |
| 4 | 51 |
| 5 | 307 |
| 6 | 819 |
| 7 | 4915 |
| 8 | 13107 |
| 9 | 78643 |
| 10 | 209715 |
| 11 | 1258291 |
| 12 | 3355443 |
| 13 | 20132659 |
| 14 | 53687091 |
| 15 | 322122547 |
| 16 | 858993459 |
| 17 | 5153960755 |
| 18 | 13743895347 |
| 19 | 82463372083 |
| 20 | 219902325555 |
| 21 | 1319413953331 |
| 22 | 3518437208883 |
| 23 | 21110623253299 |
| 24 | 56294995342131 |
| 25 | 337769972052787 |
| 26 | 900719925474099 |
[1,3,19,51,307,819,4915,13107,78643,209715, 1258291,3355443,20132659,53687091,322122547, 858993459,5153960755,13743895347,82463372083, 219902325555,1319413953331,3518437208883, 21110623253299,56294995342131,337769972052787, 900719925474099] |