The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 1 |
| 6 | 1 |
| 7 | 37 |
| 8 | 73 |
| 9 | 549 |
| 10 | 1155 |
| 11 | 18213 |
| 12 | 46753 |
| 13 | 1912543 |
| 14 | 6241489 |
| 15 | 625732277 |
| 16 | 2571374751 |
| 17 | 388840217669 |
| 18 | 1994859107661 |
| 19 | 608353553481999 |
| 20 | 3912610945442677 |
| 21 | 2428168209787780883 |
| 22 | 19568752353921733413 |
| 23 | 24097482751802550964553 |
[1,1,1,1,1,1,37,73,549,1155,18213,46753,1912543, 6241489,625732277,2571374751,388840217669, 1994859107661,608353553481999,3912610945442677, 2428168209787780883,19568752353921733413, 24097482751802550964553] |