The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 22 |
| 4 | 103 |
| 5 | 487 |
| 6 | 2276 |
| 7 | 10653 |
| 8 | 49951 |
| 9 | 234006 |
| 10 | 1096844 |
| 11 | 5140867 |
| 12 | 24096269 |
| 13 | 112943160 |
| 14 | 529386957 |
| 15 | 2481335981 |
| 16 | 11630503852 |
| 17 | 54514395378 |
| 18 | 255519475371 |
| 19 | 1197668846683 |
| 20 | 5613704209364 |
| 21 | 26312510476977 |
| 22 | 123331794880035 |
[1,4,22,103,487,2276,10653,49951,234006,1096844, 5140867,24096269,112943160,529386957,2481335981, 11630503852,54514395378,255519475371, 1197668846683,5613704209364,26312510476977, 123331794880035] |