The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 7 |
| 3 | 23 |
| 4 | 71 |
| 5 | 223 |
| 6 | 673 |
| 7 | 2027 |
| 8 | 6089 |
| 9 | 18269 |
| 10 | 54829 |
| 11 | 164503 |
| 12 | 493523 |
| 13 | 1480571 |
| 14 | 4441721 |
| 15 | 13325171 |
| 16 | 39975553 |
| 17 | 119926691 |
| 18 | 359780077 |
| 19 | 1079340313 |
| 20 | 3238020943 |
| 21 | 9714062893 |
| 22 | 29142188683 |
| 23 | 87426566057 |
| 24 | 262279698173 |
| 25 | 786839094529 |
[2,7,23,71,223,673,2027,6089,18269,54829,164503, 493523,1480571,4441721,13325171,39975553, 119926691,359780077,1079340313,3238020943, 9714062893,29142188683,87426566057,262279698173, 786839094529] |