The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 6 |
| 3 | 1 |
| 4 | 66 |
| 5 | 18 |
| 6 | 1 |
| 7 | 1056 |
| 8 | 372 |
| 9 | 36 |
| 10 | 1 |
| 11 | 22176 |
| 12 | 9240 |
| 13 | 1200 |
| 14 | 60 |
| 15 | 1 |
| 16 | 576576 |
| 17 | 271656 |
| 18 | 42840 |
| 19 | 2940 |
| 20 | 90 |
| 21 | 1 |
| 22 | 17873856 |
| 23 | 9269568 |
| 24 | 1685376 |
| 25 | 142800 |
| 26 | 6090 |
| 27 | 126 |
| 28 | 1 |
| 29 | 643458816 |
| 30 | 360847872 |
| 31 | 73313856 |
| 32 | 7254576 |
| 33 | 386400 |
| 34 | 11256 |
| 35 | 168 |
| 36 | 1 |
| 37 | 26381811456 |
| 38 | 15799069440 |
[1,6,1,66,18,1,1056,372,36,1,22176,9240,1200,60,1, 576576,271656,42840,2940,90,1,17873856,9269568, 1685376,142800,6090,126,1,643458816,360847872, 73313856,7254576,386400,11256,168,1,26381811456, 15799069440] |