The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 1 |
| 5 | 7 |
| 6 | 1 |
| 7 | 104 |
| 8 | 73 |
| 9 | 2290 |
| 10 | 889 |
| 11 | 152134 |
| 12 | 23481 |
| 13 | 12486576 |
| 14 | 1748579 |
| 15 | 3428631159 |
| 16 | 537394622 |
| 17 | 1970919353906 |
| 18 | 210642575089 |
| 19 | 2518403936450056 |
| 20 | 171343684579928 |
| 21 | 6431595589741779276 |
| 22 | 356508319334901141 |
| 23 | 39444600664282424525228 |
[1,1,3,1,7,1,104,73,2290,889,152134,23481, 12486576,1748579,3428631159,537394622, 1970919353906,210642575089,2518403936450056, 171343684579928,6431595589741779276, 356508319334901141,39444600664282424525228] |