The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 5 |
| 3 | 16 |
| 4 | 54 |
| 5 | 195 |
| 6 | 739 |
| 7 | 2898 |
| 8 | 11665 |
| 9 | 47978 |
| 10 | 201023 |
| 11 | 854393 |
| 12 | 3677078 |
| 13 | 15998576 |
| 14 | 70258094 |
| 15 | 311037123 |
| 16 | 1386937967 |
| 17 | 6224225938 |
| 18 | 28091605154 |
| 19 | 127435565082 |
| 20 | 580796534604 |
| 21 | 2658184572048 |
| 22 | 12212656631819 |
| 23 | 56307236152953 |
| 24 | 260450113138421 |
| 25 | 1208312330947453 |
| 26 | 5621241503362272 |
| 27 | 26217963341248498 |
[1,2,5,16,54,195,739,2898,11665,47978,201023, 854393,3677078,15998576,70258094,311037123, 1386937967,6224225938,28091605154,127435565082, 580796534604,2658184572048,12212656631819, 56307236152953,260450113138421,1208312330947453, 5621241503362272,26217963341248498] |