The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 5 |
| 3 | 18 |
| 4 | 65 |
| 5 | 234 |
| 6 | 859 |
| 7 | 3198 |
| 8 | 12011 |
| 9 | 45422 |
| 10 | 172745 |
| 11 | 660010 |
| 12 | 2531411 |
| 13 | 9740590 |
| 14 | 37585189 |
| 15 | 145376930 |
| 16 | 563495201 |
| 17 | 2188229290 |
| 18 | 8511640099 |
| 19 | 33157034510 |
| 20 | 129334888721 |
| 21 | 505100839930 |
| 22 | 1974764074999 |
| 23 | 7728329887670 |
| 24 | 30272839608101 |
| 25 | 118682276550082 |
| 26 | 465645693340003 |
[1,2,5,18,65,234,859,3198,12011,45422,172745, 660010,2531411,9740590,37585189,145376930, 563495201,2188229290,8511640099,33157034510, 129334888721,505100839930,1974764074999, 7728329887670,30272839608101,118682276550082, 465645693340003] |