The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 3 |
| 2 | 12 |
| 3 | 51 |
| 4 | 204 |
| 5 | 819 |
| 6 | 3276 |
| 7 | 13107 |
| 8 | 52428 |
| 9 | 209715 |
| 10 | 838860 |
| 11 | 3355443 |
| 12 | 13421772 |
| 13 | 53687091 |
| 14 | 214748364 |
| 15 | 858993459 |
| 16 | 3435973836 |
| 17 | 13743895347 |
| 18 | 54975581388 |
| 19 | 219902325555 |
| 20 | 879609302220 |
| 21 | 3518437208883 |
| 22 | 14073748835532 |
| 23 | 56294995342131 |
| 24 | 225179981368524 |
| 25 | 900719925474099 |
[3,12,51,204,819,3276,13107,52428,209715,838860, 3355443,13421772,53687091,214748364,858993459, 3435973836,13743895347,54975581388,219902325555, 879609302220,3518437208883,14073748835532, 56294995342131,225179981368524,900719925474099] |