The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 7 |
| 4 | 13 |
| 5 | 56 |
| 6 | 247 |
| 7 | 475 |
| 8 | 2108 |
| 9 | 9361 |
| 10 | 18019 |
| 11 | 80030 |
| 12 | 355453 |
| 13 | 684229 |
| 14 | 3039014 |
| 15 | 13497835 |
| 16 | 25982665 |
| 17 | 115402484 |
| 18 | 512562259 |
| 19 | 986657023 |
| 20 | 4382255360 |
| 21 | 19463867989 |
| 22 | 37466984191 |
| 23 | 166410301178 |
| 24 | 739114421305 |
| 25 | 1422758742217 |
| 26 | 6319209189386 |
[1,2,7,13,56,247,475,2108,9361,18019,80030,355453, 684229,3039014,13497835,25982665,115402484, 512562259,986657023,4382255360,19463867989, 37466984191,166410301178,739114421305, 1422758742217,6319209189386] |