The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 138 |
| 3 | 6571 |
| 4 | 353935 |
| 5 | 20694945 |
| 6 | 1276853497 |
| 7 | 81834405039 |
| 8 | 5395444806588 |
| 9 | 363600236084796 |
| 10 | 24933767742193052 |
| 11 | 1734273108108910743 |
| 12 | 122058422998192278797 |
| 13 | 8676376795137864622232 |
| 14 | 622018188741046650309066 |
| 15 | 44922343315319150402783783 |
| 16 | 3265215115112327274815579250 |
[1,4,138,6571,353935,20694945,1276853497, 81834405039,5395444806588,363600236084796, 24933767742193052,1734273108108910743, 122058422998192278797,8676376795137864622232, 622018188741046650309066, 44922343315319150402783783, 3265215115112327274815579250] |