The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 0 |
| 3 | 1 |
| 4 | 1 |
| 5 | 3 |
| 6 | 2 |
| 7 | 9 |
| 8 | 7 |
| 9 | 27 |
| 10 | 25 |
| 11 | 85 |
| 12 | 86 |
| 13 | 287 |
| 14 | 296 |
| 15 | 975 |
| 16 | 1065 |
| 17 | 3369 |
| 18 | 3825 |
| 19 | 11887 |
| 20 | 13836 |
| 21 | 42389 |
| 22 | 50597 |
| 23 | 152549 |
| 24 | 186186 |
| 25 | 554103 |
| 26 | 688494 |
| 27 | 2027304 |
| 28 | 2559958 |
| 29 | 7461971 |
| 30 | 9561298 |
| 31 | 27617581 |
| 32 | 35846863 |
| 33 | 102707431 |
| 34 | 134874639 |
| 35 | 383561963 |
| 36 | 509090498 |
| 37 | 1437822479 |
| 38 | 1927045425 |
[0,1,0,1,1,3,2,9,7,27,25,85,86,287,296,975,1065, 3369,3825,11887,13836,42389,50597,152549,186186, 554103,688494,2027304,2559958,7461971,9561298, 27617581,35846863,102707431,134874639,383561963, 509090498,1437822479,1927045425] |