The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 19 |
| 4 | 83 |
| 5 | 391 |
| 6 | 1663 |
| 7 | 7739 |
| 8 | 33812 |
| 9 | 153575 |
| 10 | 677901 |
| 11 | 3075879 |
| 12 | 13586581 |
| 13 | 61458267 |
| 14 | 272367077 |
| 15 | 1228519987 |
| 16 | 5456053443 |
| 17 | 24547516939 |
| 18 | 109153816505 |
| 19 | 490067180301 |
| 20 | 2180061001275 |
| 21 | 9772927018285 |
| 22 | 43467641569472 |
[1,4,19,83,391,1663,7739,33812,153575,677901, 3075879,13586581,61458267,272367077,1228519987, 5456053443,24547516939,109153816505,490067180301, 2180061001275,9772927018285,43467641569472] |