The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 16 |
| 3 | 56 |
| 4 | 171 |
| 5 | 530 |
| 6 | 1495 |
| 7 | 4059 |
| 8 | 10121 |
| 9 | 23476 |
| 10 | 51169 |
| 11 | 105957 |
| 12 | 210063 |
| 13 | 401043 |
| 14 | 740392 |
| 15 | 1325954 |
| 16 | 2309449 |
| 17 | 3920715 |
| 18 | 6500605 |
| 19 | 10544919 |
| 20 | 16762214 |
| 21 | 26148867 |
| 22 | 40085363 |
| 23 | 60458446 |
| 24 | 89814510 |
| 25 | 131550423 |
| 26 | 190148874 |
| 27 | 271466315 |
| 28 | 383082641 |
| 29 | 534722915 |
[4,16,56,171,530,1495,4059,10121,23476,51169, 105957,210063,401043,740392,1325954,2309449, 3920715,6500605,10544919,16762214,26148867, 40085363,60458446,89814510,131550423,190148874, 271466315,383082641,534722915] |