The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 6 |
| 3 | 8 |
| 4 | 88 |
| 5 | 292 |
| 6 | 1774 |
| 7 | 7676 |
| 8 | 39844 |
| 9 | 186996 |
| 10 | 927134 |
| 11 | 4460016 |
| 12 | 21812696 |
| 13 | 105716132 |
| 14 | 514912230 |
| 15 | 2501152692 |
| 16 | 12167375908 |
| 17 | 59142175940 |
| 18 | 287602784246 |
| 19 | 1398239939960 |
| 20 | 6798750327544 |
| 21 | 33055539575012 |
| 22 | 160722650037822 |
| 23 | 781448253270316 |
[0,6,8,88,292,1774,7676,39844,186996,927134, 4460016,21812696,105716132,514912230,2501152692, 12167375908,59142175940,287602784246, 1398239939960,6798750327544,33055539575012, 160722650037822,781448253270316] |