The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 9 |
| 3 | 33 |
| 4 | 129 |
| 5 | 511 |
| 6 | 2110 |
| 7 | 8855 |
| 8 | 37630 |
| 9 | 162562 |
| 10 | 707441 |
| 11 | 3105186 |
| 12 | 13739266 |
| 13 | 61089049 |
| 14 | 273188714 |
| 15 | 1227301479 |
| 16 | 5534051578 |
| 17 | 25051273980 |
| 18 | 113748350238 |
| 19 | 517968113869 |
| 20 | 2365096349789 |
| 21 | 10823958151853 |
| 22 | 49646711304843 |
| 23 | 228176908323882 |
| 24 | 1050601462096454 |
| 25 | 4845768031863803 |
| 26 | 22385650120512045 |
| 27 | 103565619746939425 |
[1,3,9,33,129,511,2110,8855,37630,162562,707441, 3105186,13739266,61089049,273188714,1227301479, 5534051578,25051273980,113748350238,517968113869, 2365096349789,10823958151853,49646711304843, 228176908323882,1050601462096454,4845768031863803, 22385650120512045,103565619746939425] |