The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 2 | 1 |
| 3 | 5 |
| 4 | 15 |
| 5 | 47 |
| 6 | 102 |
| 7 | 276 |
| 8 | 578 |
| 9 | 1261 |
| 10 | 2465 |
| 11 | 5362 |
| 12 | 9285 |
| 13 | 18900 |
| 14 | 33269 |
| 15 | 58171 |
| 16 | 99328 |
| 17 | 181514 |
| 18 | 287239 |
| 19 | 502116 |
| 20 | 775710 |
| 21 | 1239710 |
| 22 | 1956334 |
| 23 | 3210736 |
| 24 | 4660786 |
| 25 | 7297823 |
| 26 | 10997235 |
| 27 | 16536803 |
[1,5,15,47,102,276,578,1261,2465,5362,9285,18900, 33269,58171,99328,181514,287239,502116,775710, 1239710,1956334,3210736,4660786,7297823,10997235, 16536803] |