The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 21 |
| 5 | 39 |
| 6 | 273 |
| 7 | 507 |
| 8 | 3081 |
| 9 | 3549 |
| 10 | 21567 |
| 11 | 40053 |
| 12 | 78117 |
| 13 | 280371 |
| 14 | 343239 |
| 15 | 546819 |
| 16 | 1015521 |
| 17 | 2056899 |
| 18 | 2402673 |
| 19 | 5998317 |
| 20 | 6171243 |
| 21 | 7108647 |
| 22 | 8740173 |
| 23 | 12338859 |
| 24 | 14398293 |
| 25 | 18988203 |
| 26 | 27115881 |
| 27 | 41988219 |
| 28 | 43198701 |
| 29 | 47727771 |
| 30 | 55431363 |
[1,3,7,21,39,273,507,3081,3549,21567,40053,78117, 280371,343239,546819,1015521,2056899,2402673, 5998317,6171243,7108647,8740173,12338859,14398293, 18988203,27115881,41988219,43198701,47727771, 55431363] |