The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 4 |
| 3 | 6 |
| 4 | 20 |
| 5 | 34 |
| 6 | 105 |
| 7 | 191 |
| 8 | 563 |
| 9 | 1071 |
| 10 | 3057 |
| 11 | 6007 |
| 12 | 16745 |
| 13 | 33729 |
| 14 | 92332 |
| 15 | 189662 |
| 16 | 511812 |
| 17 | 1068178 |
| 18 | 2849404 |
| 19 | 6025594 |
| 20 | 15921514 |
| 21 | 34043204 |
| 22 | 89242582 |
| 23 | 192621212 |
| 24 | 501574732 |
| 25 | 1091400122 |
| 26 | 2825710822 |
| 27 | 6192005260 |
| 28 | 15952433940 |
| 29 | 35172854946 |
[1,1,4,6,20,34,105,191,563,1071,3057,6007,16745, 33729,92332,189662,511812,1068178,2849404,6025594, 15921514,34043204,89242582,192621212,501574732, 1091400122,2825710822,6192005260,15952433940, 35172854946] |