The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 3 |
| 3 | 13 |
| 4 | 51 |
| 5 | 205 |
| 6 | 819 |
| 7 | 3277 |
| 8 | 13107 |
| 9 | 52429 |
| 10 | 209715 |
| 11 | 838861 |
| 12 | 3355443 |
| 13 | 13421773 |
| 14 | 53687091 |
| 15 | 214748365 |
| 16 | 858993459 |
| 17 | 3435973837 |
| 18 | 13743895347 |
| 19 | 54975581389 |
| 20 | 219902325555 |
| 21 | 879609302221 |
| 22 | 3518437208883 |
| 23 | 14073748835533 |
[0,1,3,13,51,205,819,3277,13107,52429,209715, 838861,3355443,13421773,53687091,214748365, 858993459,3435973837,13743895347,54975581389, 219902325555,879609302221,3518437208883, 14073748835533] |