The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | 3 |
| 3 | 8 |
| 4 | 20 |
| 5 | 49 |
| 6 | 123 |
| 7 | 319 |
| 8 | 849 |
| 9 | 2294 |
| 10 | 6250 |
| 11 | 17112 |
| 12 | 47013 |
| 13 | 129605 |
| 14 | 358838 |
| 15 | 998805 |
| 16 | 2796093 |
| 17 | 7869800 |
| 18 | 22251147 |
| 19 | 63141639 |
| 20 | 179701239 |
| 21 | 512744599 |
| 22 | 1466635089 |
| 23 | 4205423895 |
| 24 | 12087339723 |
| 25 | 34816804310 |
| 26 | 100469592521 |
| 27 | 290336059740 |
| 28 | 839932833290 |
| 29 | 2432050970420 |
| 30 | 7047731703137 |
| 31 | 20440131344750 |
| 32 | 59334695322383 |
| 33 | 172409162871823 |
| 34 | 501489513690423 |
| 35 | 1460214792034791 |
[0,1,3,8,20,49,123,319,849,2294,6250,17112,47013, 129605,358838,998805,2796093,7869800,22251147, 63141639,179701239,512744599,1466635089, 4205423895,12087339723,34816804310,100469592521, 290336059740,839932833290,2432050970420, 7047731703137,20440131344750,59334695322383, 172409162871823,501489513690423,1460214792034791] |