The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 14 |
| 5 | 45 |
| 6 | 163 |
| 7 | 657 |
| 8 | 2910 |
| 9 | 14020 |
| 10 | 72860 |
| 11 | 405610 |
| 12 | 2404875 |
| 13 | 15111771 |
| 14 | 100221229 |
| 15 | 698963970 |
| 16 | 5110106721 |
| 17 | 39055225870 |
| 18 | 311266844753 |
| 19 | 2581286974308 |
| 20 | 22229605651905 |
| 21 | 198447018330411 |
| 22 | 1833460269345737 |
| 23 | 17505367714550240 |
[1,2,5,14,45,163,657,2910,14020,72860,405610, 2404875,15111771,100221229,698963970,5110106721, 39055225870,311266844753,2581286974308, 22229605651905,198447018330411,1833460269345737, 17505367714550240] |