The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 3 |
| 4 | 8 |
| 5 | 15 |
| 6 | 30 |
| 7 | 54 |
| 8 | 138 |
| 9 | 281 |
| 10 | 562 |
| 11 | 1069 |
| 12 | 2700 |
| 13 | 5682 |
| 14 | 11364 |
| 15 | 22196 |
| 16 | 55756 |
| 17 | 119437 |
| 18 | 238874 |
| 19 | 473871 |
| 20 | 1186616 |
| 21 | 2570259 |
| 22 | 5140518 |
| 23 | 10302254 |
| 24 | 25745026 |
| 25 | 56189736 |
| 26 | 112379472 |
| 27 | 226854572 |
| 28 | 566088616 |
| 29 | 1242353004 |
| 30 | 2484706008 |
[1,1,2,3,8,15,30,54,138,281,562,1069,2700,5682, 11364,22196,55756,119437,238874,473871,1186616, 2570259,5140518,10302254,25745026,56189736, 112379472,226854572,566088616,1242353004, 2484706008] |