The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 2 | 1 |
| 3 | 3 |
| 4 | 15 |
| 5 | 111 |
| 6 | 1131 |
| 7 | 15123 |
| 8 | 256335 |
| 9 | 5364471 |
| 10 | 135751731 |
| 11 | 4084163643 |
| 12 | 144039790455 |
| 13 | 5884504366431 |
| 14 | 275643776229531 |
| 15 | 14673941326078563 |
| 16 | 880908054392169375 |
| 17 | 59226468571935857991 |
| 18 | 4432461082611507366531 |
| 19 | 367227420727722013775883 |
| 20 | 33514867695588319595233095 |
[1,3,15,111,1131,15123,256335,5364471,135751731, 4084163643,144039790455,5884504366431, 275643776229531,14673941326078563, 880908054392169375,59226468571935857991, 4432461082611507366531,367227420727722013775883, 33514867695588319595233095] |