The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 6 |
| 2 | 28 |
| 3 | 104 |
| 4 | 342 |
| 5 | 1016 |
| 6 | 2808 |
| 7 | 7296 |
| 8 | 18044 |
| 9 | 42750 |
| 10 | 97656 |
| 11 | 215992 |
| 12 | 464360 |
| 13 | 973176 |
| 14 | 1993328 |
| 15 | 3998592 |
| 16 | 7870038 |
| 17 | 15221232 |
| 18 | 28968084 |
| 19 | 54311736 |
| 20 | 100421688 |
| 21 | 183281904 |
| 22 | 330468216 |
| 23 | 589084288 |
| 24 | 1038850488 |
| 25 | 1813500030 |
| 26 | 3135518440 |
| 27 | 5372110496 |
| 28 | 9124793472 |
| 29 | 15371832424 |
[1,6,28,104,342,1016,2808,7296,18044,42750,97656, 215992,464360,973176,1993328,3998592,7870038, 15221232,28968084,54311736,100421688,183281904, 330468216,589084288,1038850488,1813500030, 3135518440,5372110496,9124793472,15371832424] |