The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 7 |
| 3 | 247 |
| 4 | 1777 |
| 5 | 62737 |
| 6 | 451351 |
| 7 | 15934951 |
| 8 | 114641377 |
| 9 | 4047414817 |
| 10 | 29118458407 |
| 11 | 1028027428567 |
| 12 | 7395973794001 |
| 13 | 261114919441201 |
| 14 | 1878548225217847 |
| 15 | 66322161510636487 |
| 16 | 477143853231539137 |
| 17 | 16845567908782226497 |
| 18 | 121192660172585722951 |
| 19 | 4278707926669174893751 |
[1,7,247,1777,62737,451351,15934951,114641377, 4047414817,29118458407,1028027428567, 7395973794001,261114919441201,1878548225217847, 66322161510636487,477143853231539137, 16845567908782226497,121192660172585722951, 4278707926669174893751] |