The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 2 |
| 2 | 4 |
| 3 | 14 |
| 4 | 57 |
| 5 | 286 |
| 6 | 1717 |
| 7 | 12024 |
| 8 | 96198 |
| 9 | 865785 |
| 10 | 8657857 |
| 11 | 95236427 |
| 12 | 1142837124 |
| 13 | 14856882614 |
| 14 | 207996356596 |
| 15 | 3119945348943 |
| 16 | 49919125583092 |
| 17 | 848625134912575 |
| 18 | 15275252428426350 |
| 19 | 290229796140100651 |
| 20 | 5804595922802013034 |
[2,4,14,57,286,1717,12024,96198,865785,8657857, 95236427,1142837124,14856882614,207996356596, 3119945348943,49919125583092,848625134912575, 15275252428426350,290229796140100651, 5804595922802013034] |