The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 7 |
| 4 | 32 |
| 5 | 174 |
| 6 | 1071 |
| 7 | 7281 |
| 8 | 53943 |
| 9 | 432555 |
| 10 | 3743146 |
| 11 | 34934853 |
| 12 | 351853883 |
| 13 | 3827477399 |
| 14 | 44985837602 |
| 15 | 570985992828 |
| 16 | 7814212692498 |
| 17 | 115024461077654 |
| 18 | 1815588345261996 |
| 19 | 30628743324667923 |
| 20 | 550414603283527315 |
| 21 | 10503650627005928698 |
[1,1,2,7,32,174,1071,7281,53943,432555,3743146, 34934853,351853883,3827477399,44985837602, 570985992828,7814212692498,115024461077654, 1815588345261996,30628743324667923, 550414603283527315,10503650627005928698] |