The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 216 |
| 2 | 986 |
| 3 | 4368 |
| 4 | 19446 |
| 5 | 79200 |
| 6 | 311498 |
| 7 | 1219944 |
| 8 | 4617079 |
| 9 | 17036428 |
| 10 | 62297886 |
| 11 | 224152970 |
| 12 | 793463094 |
| 13 | 2782588100 |
| 14 | 9662944274 |
| 15 | 33203799944 |
| 16 | 113195928313 |
| 17 | 383180556700 |
| 18 | 1287749650878 |
| 19 | 4300782679270 |
| 20 | 14285051453226 |
| 21 | 47196108008844 |
[216,986,4368,19446,79200,311498,1219944,4617079, 17036428,62297886,224152970,793463094,2782588100, 9662944274,33203799944,113195928313,383180556700, 1287749650878,4300782679270,14285051453226, 47196108008844] |