The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 220 |
| 2 | 1210 |
| 3 | 6655 |
| 4 | 34243 |
| 5 | 180829 |
| 6 | 963886 |
| 7 | 5093737 |
| 8 | 26932543 |
| 9 | 142701909 |
| 10 | 755538278 |
| 11 | 3999038946 |
| 12 | 21172904049 |
| 13 | 112098384491 |
| 14 | 593455432350 |
| 15 | 3141868198978 |
| 16 | 16633824615067 |
| 17 | 88062718713584 |
| 18 | 466221475528171 |
| 19 | 2468274573927916 |
[220,1210,6655,34243,180829,963886,5093737, 26932543,142701909,755538278,3999038946, 21172904049,112098384491,593455432350, 3141868198978,16633824615067,88062718713584, 466221475528171,2468274573927916] |