The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 2 |
| 5 | 3 |
| 6 | 9 |
| 7 | 12 |
| 8 | 15 |
| 9 | 40 |
| 10 | 51 |
| 11 | 63 |
| 12 | 175 |
| 13 | 220 |
| 14 | 270 |
| 15 | 759 |
| 16 | 945 |
| 17 | 1155 |
| 18 | 3311 |
| 19 | 4102 |
| 20 | 5005 |
| 21 | 14547 |
| 22 | 17955 |
| 23 | 21875 |
| 24 | 64275 |
| 25 | 79116 |
| 26 | 96288 |
| 27 | 285413 |
| 28 | 350568 |
| 29 | 426303 |
| 30 | 1272601 |
| 31 | 1560449 |
| 32 | 1896279 |
| 33 | 5694129 |
| 34 | 6972339 |
| 35 | 8468163 |
| 36 | 25554035 |
| 37 | 31253950 |
[0,0,1,2,3,9,12,15,40,51,63,175,220,270,759,945, 1155,3311,4102,5005,14547,17955,21875,64275,79116, 96288,285413,350568,426303,1272601,1560449, 1896279,5694129,6972339,8468163,25554035,31253950] |