The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 12 |
| 3 | 36 |
| 4 | 144 |
| 5 | 465 |
| 6 | 2061 |
| 7 | 6243 |
| 8 | 25062 |
| 9 | 111246 |
| 10 | 334104 |
| 11 | 1335315 |
| 12 | 4342251 |
| 13 | 16360113 |
| 14 | 55440342 |
| 15 | 232651356 |
| 16 | 1031614434 |
| 17 | 3125446635 |
| 18 | 12413006541 |
| 19 | 40542026253 |
| 20 | 152256115122 |
| 21 | 520134351366 |
| 22 | 2160436414464 |
[1,3,12,36,144,465,2061,6243,25062,111246,334104, 1335315,4342251,16360113,55440342,232651356, 1031614434,3125446635,12413006541,40542026253, 152256115122,520134351366,2160436414464] |