The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 8 |
| 4 | 17 |
| 5 | 36 |
| 6 | 71 |
| 7 | 144 |
| 8 | 289 |
| 9 | 594 |
| 10 | 1231 |
| 11 | 2602 |
| 12 | 5573 |
| 13 | 12128 |
| 14 | 26727 |
| 15 | 59668 |
| 16 | 134729 |
| 17 | 307618 |
| 18 | 709503 |
| 19 | 1652402 |
| 20 | 3883445 |
| 21 | 9206712 |
[1,3,8,17,36,71,144,289,594,1231,2602,5573,12128, 26727,59668,134729,307618,709503,1652402,3883445, 9206712] |