The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 11 |
| 3 | 124 |
| 4 | 841 |
| 5 | 3844 |
| 6 | 23571 |
| 7 | 159164 |
| 8 | 903201 |
| 9 | 5174084 |
| 10 | 32096731 |
| 11 | 192836604 |
| 12 | 1128271161 |
| 13 | 6758574724 |
| 14 | 40676603491 |
| 15 | 241740656444 |
| 16 | 1439437080721 |
| 17 | 8616705389764 |
| 18 | 51443701799851 |
| 19 | 306634988322684 |
| 20 | 1830991983267881 |
[1,4,11,124,841,3844,23571,159164,903201,5174084, 32096731,192836604,1128271161,6758574724, 40676603491,241740656444,1439437080721, 8616705389764,51443701799851,306634988322684, 1830991983267881] |