The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 37 |
| 4 | 532 |
| 5 | 9994 |
| 6 | 226252 |
| 7 | 5910445 |
| 8 | 173581060 |
| 9 | 5634589906 |
| 10 | 199792389160 |
| 11 | 7671942375898 |
| 12 | 316936631324368 |
| 13 | 14011781050744984 |
| 14 | 660054967923455212 |
| 15 | 33008607551445324157 |
| 16 | 1746771084107236755604 |
| 17 | 97536010045722766992778 |
| 18 | 5731874036042145864368824 |
[1,1,4,37,532,9994,226252,5910445,173581060, 5634589906,199792389160,7671942375898, 316936631324368,14011781050744984, 660054967923455212,33008607551445324157, 1746771084107236755604,97536010045722766992778, 5731874036042145864368824] |