The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 7 |
| 4 | 23 |
| 5 | 67 |
| 6 | 237 |
| 7 | 805 |
| 8 | 2885 |
| 9 | 10509 |
| 10 | 39807 |
| 11 | 149141 |
| 12 | 579341 |
| 13 | 2263291 |
| 14 | 8905423 |
| 15 | 35534405 |
| 16 | 143264965 |
| 17 | 578222653 |
| 18 | 2363626881 |
| 19 | 9716589785 |
| 20 | 40034773345 |
| 21 | 166371602771 |
| 22 | 694827197783 |
| 23 | 2906176160045 |
| 24 | 12238781990415 |
| 25 | 51736232838013 |
| 26 | 219012786708273 |
| 27 | 932089077079915 |
| 28 | 3979322489517421 |
[1,1,3,7,23,67,237,805,2885,10509,39807,149141, 579341,2263291,8905423,35534405,143264965, 578222653,2363626881,9716589785,40034773345, 166371602771,694827197783,2906176160045, 12238781990415,51736232838013,219012786708273, 932089077079915,3979322489517421] |