The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 12 |
| 3 | 126 |
| 4 | 1560 |
| 5 | 23325 |
| 6 | 411768 |
| 7 | 8388604 |
| 8 | 193710240 |
| 9 | 4999999995 |
| 10 | 142655835300 |
| 11 | 4458050224122 |
| 12 | 151437553296120 |
| 13 | 5556003412779001 |
| 14 | 218946945190429680 |
| 15 | 9223372036854775800 |
| 16 | 413620130943168382080 |
| 17 | 19673204037648268787703 |
[1,12,126,1560,23325,411768,8388604,193710240, 4999999995,142655835300,4458050224122, 151437553296120,5556003412779001, 218946945190429680,9223372036854775800, 413620130943168382080,19673204037648268787703] |