The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 8 |
| 3 | 36 |
| 4 | 177 |
| 5 | 920 |
| 6 | 4972 |
| 7 | 27656 |
| 8 | 157283 |
| 9 | 910378 |
| 10 | 5345408 |
| 11 | 31761232 |
| 12 | 190616428 |
| 13 | 1153815776 |
| 14 | 7035931524 |
| 15 | 43182501648 |
| 16 | 266538732951 |
| 17 | 1653488312726 |
| 18 | 10303782450616 |
| 19 | 64468708569236 |
| 20 | 404844870033361 |
| 21 | 2550760645474016 |
| 22 | 16120015360974736 |
| 23 | 102156302157189536 |
[1,2,8,36,177,920,4972,27656,157283,910378, 5345408,31761232,190616428,1153815776,7035931524, 43182501648,266538732951,1653488312726, 10303782450616,64468708569236,404844870033361, 2550760645474016,16120015360974736, 102156302157189536] |