The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 3 | 0 |
| 4 | 0 |
| 5 | 4 |
| 6 | 6 |
| 7 | 4 |
| 8 | 22 |
| 9 | 50 |
| 10 | 118 |
| 11 | 186 |
| 12 | 704 |
| 13 | 1420 |
| 14 | 3678 |
| 15 | 8470 |
| 16 | 23668 |
| 17 | 54792 |
| 18 | 146181 |
| 19 | 362476 |
| 20 | 967161 |
| 21 | 2432178 |
| 22 | 6515652 |
| 23 | 16829286 |
| 24 | 44983125 |
| 25 | 117818862 |
| 26 | 316461687 |
| 27 | 837468916 |
| 28 | 2250992464 |
| 29 | 6002841492 |
| 30 | 16168909200 |
| 31 | 43313559104 |
[0,0,4,6,4,22,50,118,186,704,1420,3678,8470,23668, 54792,146181,362476,967161,2432178,6515652, 16829286,44983125,117818862,316461687,837468916, 2250992464,6002841492,16168909200,43313559104] |