The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 3 |
| 3 | 3 |
| 4 | 21 |
| 5 | 27 |
| 6 | 177 |
| 7 | 231 |
| 8 | 1509 |
| 9 | 1971 |
| 10 | 12873 |
| 11 | 16815 |
| 12 | 109821 |
| 13 | 143451 |
| 14 | 936897 |
| 15 | 1223799 |
| 16 | 7992789 |
| 17 | 10440387 |
| 18 | 68187513 |
| 19 | 89068287 |
| 20 | 581716461 |
| 21 | 759853035 |
| 22 | 4962698097 |
| 23 | 6482404167 |
| 24 | 42337417029 |
| 25 | 55302225363 |
| 26 | 361185960873 |
| 27 | 471790411599 |
[0,3,3,21,27,177,231,1509,1971,12873,16815,109821, 143451,936897,1223799,7992789,10440387,68187513, 89068287,581716461,759853035,4962698097, 6482404167,42337417029,55302225363,361185960873, 471790411599] |