The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 10 |
| 4 | 43 |
| 5 | 247 |
| 6 | 1926 |
| 7 | 19414 |
| 8 | 236328 |
| 9 | 3323205 |
| 10 | 52705090 |
| 11 | 929220616 |
| 12 | 18022413696 |
| 13 | 381329741071 |
| 14 | 8740799344746 |
| 15 | 215767673761410 |
| 16 | 5706697328974816 |
| 17 | 160994864601428425 |
| 18 | 4825786965074938818 |
| 19 | 153160879869533780812 |
| 20 | 5131078453592054013360 |
| 21 | 180944693884489748335731 |
[1,1,3,10,43,247,1926,19414,236328,3323205, 52705090,929220616,18022413696,381329741071, 8740799344746,215767673761410,5706697328974816, 160994864601428425,4825786965074938818, 153160879869533780812,5131078453592054013360, 180944693884489748335731] |