The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 56 |
| 3 | 974 |
| 4 | 12164 |
| 5 | 180886 |
| 6 | 2228098 |
| 7 | 31650312 |
| 8 | 390211138 |
| 9 | 5426848414 |
| 10 | 67338401270 |
| 11 | 924586466428 |
| 12 | 11556584240334 |
| 13 | 157226907539810 |
| 14 | 1978592816499310 |
| 15 | 26727350706141760 |
| 16 | 338342532540889892 |
| 17 | 4544157885733729912 |
[4,56,974,12164,180886,2228098,31650312,390211138, 5426848414,67338401270,924586466428, 11556584240334,157226907539810,1978592816499310, 26727350706141760,338342532540889892, 4544157885733729912] |