The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 9 |
| 4 | 38 |
| 5 | 140 |
| 6 | 604 |
| 7 | 2449 |
| 8 | 10927 |
| 9 | 46990 |
| 10 | 214160 |
| 11 | 949940 |
| 12 | 4396411 |
| 13 | 19899975 |
| 14 | 93160452 |
| 15 | 428506551 |
| 16 | 2022890300 |
| 17 | 9411578929 |
| 18 | 44720051414 |
| 19 | 209872108538 |
| 20 | 1002525113773 |
| 21 | 4739546631453 |
| 22 | 22736550385796 |
| 23 | 108110600640944 |
| 24 | 520463523561756 |
| 25 | 2486388168617500 |
| 26 | 12006128842805812 |
| 27 | 57592279400912576 |
[1,1,3,9,38,140,604,2449,10927,46990,214160, 949940,4396411,19899975,93160452,428506551, 2022890300,9411578929,44720051414,209872108538, 1002525113773,4739546631453,22736550385796, 108110600640944,520463523561756,2486388168617500, 12006128842805812,57592279400912576] |