The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 5 |
| 3 | 25 |
| 4 | 97 |
| 5 | 411 |
| 6 | 1897 |
| 7 | 8741 |
| 8 | 41689 |
| 9 | 201985 |
| 10 | 987407 |
| 11 | 4891069 |
| 12 | 24457873 |
| 13 | 123131033 |
| 14 | 623695509 |
| 15 | 3174983801 |
| 16 | 16227954653 |
| 17 | 83226630287 |
| 18 | 428047598133 |
| 19 | 2206766393985 |
| 20 | 11399915802567 |
| 21 | 58993096946055 |
| 22 | 305739808201773 |
| 23 | 1586610751415691 |
[1,5,25,97,411,1897,8741,41689,201985,987407, 4891069,24457873,123131033,623695509,3174983801, 16227954653,83226630287,428047598133, 2206766393985,11399915802567,58993096946055, 305739808201773,1586610751415691] |