The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 1 |
| 7 | 12 |
| 8 | 142 |
| 9 | 1346 |
| 10 | 11511 |
| 11 | 89974 |
| 12 | 662673 |
| 13 | 4662574 |
| 14 | 31724723 |
| 15 | 210361046 |
| 16 | 1367510184 |
| 17 | 8752976610 |
| 18 | 55343946628 |
| 19 | 346541488998 |
| 20 | 2153041576027 |
| 21 | 13292844257186 |
| 22 | 81652683460145 |
| 23 | 499484958151630 |
[0,0,0,0,0,1,12,142,1346,11511,89974,662673, 4662574,31724723,210361046,1367510184,8752976610, 55343946628,346541488998,2153041576027, 13292844257186,81652683460145,499484958151630] |