The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 4 |
| 1 | 10 |
| 2 | 25 |
| 3 | 70 |
| 4 | 238 |
| 5 | 901 |
| 6 | 3445 |
| 7 | 13390 |
| 8 | 52942 |
| 9 | 210226 |
| 10 | 838450 |
| 11 | 3350725 |
| 12 | 13393093 |
| 13 | 53547790 |
| 14 | 214151950 |
| 15 | 856558645 |
| 16 | 3426077749 |
| 17 | 13703917774 |
| 18 | 54815043790 |
| 19 | 219258602290 |
| 20 | 877031899954 |
| 21 | 3508124454085 |
| 22 | 14032487779525 |
| 23 | 56129938535185 |
| 24 | 224519713993489 |
| 25 | 898078755310654 |
[4,10,25,70,238,901,3445,13390,52942,210226, 838450,3350725,13393093,53547790,214151950, 856558645,3426077749,13703917774,54815043790, 219258602290,877031899954,3508124454085, 14032487779525,56129938535185,224519713993489, 898078755310654] |