The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 4 |
| 3 | 13 |
| 4 | 28 |
| 5 | 1199 |
| 6 | 239 |
| 7 | 113149 |
| 8 | 1487 |
| 9 | 14345663 |
| 10 | 292223 |
| 11 | 17110600987 |
| 12 | 14849671 |
| 13 | 545242142639 |
| 14 | 961780559 |
| 15 | 1704615588759647 |
| 16 | 856088316689 |
| 17 | 7836371329207844977 |
| 18 | 1103759659545457 |
| 19 | 16895087931630048788047 |
| 20 | 59954362566895631 |
| 21 | 2699144613568894213138579 |
| 22 | 28918424475964028179 |
[0,1,4,13,28,1199,239,113149,1487,14345663,292223, 17110600987,14849671,545242142639,961780559, 1704615588759647,856088316689,7836371329207844977, 1103759659545457,16895087931630048788047, 59954362566895631,2699144613568894213138579, 28918424475964028179] |