The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 8 |
| 4 | 15 |
| 5 | 22 |
| 6 | 78 |
| 7 | 190 |
| 8 | 400 |
| 9 | 1051 |
| 10 | 2535 |
| 11 | 7456 |
| 12 | 18453 |
| 13 | 47188 |
| 14 | 126687 |
| 15 | 358191 |
| 16 | 954794 |
| 17 | 2455349 |
| 18 | 6649728 |
| 19 | 18661770 |
| 20 | 50325066 |
| 21 | 134032193 |
| 22 | 366103529 |
| 23 | 1031003534 |
| 24 | 2817678326 |
| 25 | 7634389540 |
| 26 | 20930031893 |
| 27 | 59436464774 |
| 28 | 163683320620 |
| 29 | 447761993141 |
[1,1,8,15,22,78,190,400,1051,2535,7456,18453, 47188,126687,358191,954794,2455349,6649728, 18661770,50325066,134032193,366103529,1031003534, 2817678326,7634389540,20930031893,59436464774, 163683320620,447761993141] |