The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 8 |
| 2 | 52 |
| 3 | 372 |
| 4 | 2894 |
| 5 | 23966 |
| 6 | 208086 |
| 7 | 1874508 |
| 8 | 17390158 |
| 9 | 165248499 |
| 10 | 1601857338 |
| 11 | 15790898316 |
| 12 | 157915304928 |
| 13 | 1598927475749 |
| 14 | 16365689821454 |
| 15 | 169113248927772 |
| 16 | 1762344520554606 |
| 17 | 18504654979649615 |
| 18 | 195620858324078190 |
| 19 | 2080695883684277190 |
| 20 | 22254407183551916850 |
[0,8,52,372,2894,23966,208086,1874508,17390158, 165248499,1601857338,15790898316,157915304928, 1598927475749,16365689821454,169113248927772, 1762344520554606,18504654979649615, 195620858324078190,2080695883684277190, 22254407183551916850] |