The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 3 |
| 4 | 7 |
| 5 | 18 |
| 6 | 70 |
| 7 | 317 |
| 8 | 1825 |
| 9 | 11805 |
| 10 | 88212 |
| 11 | 727731 |
| 12 | 6660103 |
| 13 | 66377942 |
| 14 | 718681969 |
| 15 | 8376682083 |
| 16 | 104703957902 |
| 17 | 1395883946839 |
| 18 | 19777652272297 |
| 19 | 296686846198829 |
| 20 | 4697959440255354 |
| 21 | 78299282813403618 |
| 22 | 1370127872827224359 |
| 23 | 25114095425698971152 |
| 24 | 481202765468970358153 |
[1,1,2,3,7,18,70,317,1825,11805,88212,727731, 6660103,66377942,718681969,8376682083, 104703957902,1395883946839,19777652272297, 296686846198829,4697959440255354, 78299282813403618,1370127872827224359, 25114095425698971152,481202765468970358153] |