The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 42 |
| 4 | 728 |
| 5 | 17630 |
| 6 | 548532 |
| 7 | 20852370 |
| 8 | 936655792 |
| 9 | 48540537702 |
| 10 | 2850727359500 |
| 11 | 187107038833946 |
| 12 | 13572973331551944 |
| 13 | 1078343465147156910 |
| 14 | 93119965280416893028 |
| 15 | 8684514946963752624930 |
| 16 | 869915871265946242868576 |
| 17 | 93146889134541855185069942 |
| 18 | 10617155946603647157142073916 |
[1,4,42,728,17630,548532,20852370,936655792, 48540537702,2850727359500,187107038833946, 13572973331551944,1078343465147156910, 93119965280416893028,8684514946963752624930, 869915871265946242868576, 93146889134541855185069942, 10617155946603647157142073916] |