The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 8 |
| 4 | 15 |
| 5 | 32 |
| 6 | 61 |
| 7 | 145 |
| 8 | 297 |
| 9 | 658 |
| 10 | 1352 |
| 11 | 2975 |
| 12 | 6240 |
| 13 | 13565 |
| 14 | 28609 |
| 15 | 61801 |
| 16 | 131106 |
| 17 | 282136 |
| 18 | 600239 |
| 19 | 1288448 |
| 20 | 2746557 |
| 21 | 5887025 |
| 22 | 12563881 |
| 23 | 26904370 |
| 24 | 57460200 |
| 25 | 122975935 |
| 26 | 262760096 |
| 27 | 562158461 |
| 28 | 1201484193 |
| 29 | 2569940969 |
| 30 | 5493595714 |
[1,2,8,15,32,61,145,297,658,1352,2975,6240,13565, 28609,61801,131106,282136,600239,1288448,2746557, 5887025,12563881,26904370,57460200,122975935, 262760096,562158461,1201484193,2569940969, 5493595714] |