The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 7 |
| 4 | 31 |
| 5 | 167 |
| 6 | 999 |
| 7 | 6495 |
| 8 | 44619 |
| 9 | 319463 |
| 10 | 2356406 |
| 11 | 17775821 |
| 12 | 136405506 |
| 13 | 1060866006 |
| 14 | 8339982193 |
| 15 | 66147792753 |
| 16 | 528559162227 |
| 17 | 4250413757583 |
| 18 | 34368723106860 |
| 19 | 279254390054538 |
| 20 | 2278795583070154 |
| 21 | 18667432144042678 |
| 22 | 153452484745198722 |
[1,2,7,31,167,999,6495,44619,319463,2356406, 17775821,136405506,1060866006,8339982193, 66147792753,528559162227,4250413757583, 34368723106860,279254390054538,2278795583070154, 18667432144042678,153452484745198722] |