The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 6 |
| 4 | 23 |
| 5 | 62 |
| 6 | 262 |
| 7 | 812 |
| 8 | 3573 |
| 9 | 12012 |
| 10 | 54270 |
| 11 | 193053 |
| 12 | 888926 |
| 13 | 3295073 |
| 14 | 15374504 |
| 15 | 58782452 |
| 16 | 276979000 |
| 17 | 1085072796 |
| 18 | 5152041461 |
| 19 | 20583672366 |
| 20 | 98328543277 |
| 21 | 399250355193 |
| 22 | 1916609557545 |
| 23 | 7888286150870 |
| 24 | 38021519436246 |
| 25 | 158300490287993 |
| 26 | 765598638786988 |
| 27 | 3219300356467260 |
| 28 | 15614479279145606 |
[1,1,3,6,23,62,262,812,3573,12012,54270,193053, 888926,3295073,15374504,58782452,276979000, 1085072796,5152041461,20583672366,98328543277, 399250355193,1916609557545,7888286150870, 38021519436246,158300490287993,765598638786988, 3219300356467260,15614479279145606] |