The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 252 |
| 2 | 838 |
| 3 | 2776 |
| 4 | 9258 |
| 5 | 31220 |
| 6 | 105954 |
| 7 | 361344 |
| 8 | 1236058 |
| 9 | 4237556 |
| 10 | 14549610 |
| 11 | 50012080 |
| 12 | 172050098 |
| 13 | 592248148 |
| 14 | 2039649282 |
| 15 | 7026884288 |
| 16 | 24215293674 |
| 17 | 83465955764 |
| 18 | 287740551770 |
| 19 | 992085339216 |
| 20 | 3420905014178 |
| 21 | 11796889975188 |
| 22 | 40683768017330 |
[252,838,2776,9258,31220,105954,361344,1236058, 4237556,14549610,50012080,172050098,592248148, 2039649282,7026884288,24215293674,83465955764, 287740551770,992085339216,3420905014178, 11796889975188,40683768017330] |