The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 1 |
| 6 | 1 |
| 7 | 8 |
| 8 | 19 |
| 9 | 32 |
| 10 | 51 |
| 11 | 140 |
| 12 | 477 |
| 13 | 1662 |
| 14 | 6189 |
| 15 | 24619 |
| 16 | 109450 |
| 17 | 533450 |
| 18 | 2859993 |
| 19 | 16886952 |
| 20 | 110380054 |
| 21 | 797354362 |
| 22 | 6460189913 |
| 23 | 58366269898 |
| 24 | 572562441744 |
| 25 | 6143132227217 |
| 26 | 72768344185209 |
[1,1,1,1,1,1,8,19,32,51,140,477,1662,6189,24619, 109450,533450,2859993,16886952,110380054, 797354362,6460189913,58366269898,572562441744, 6143132227217,72768344185209] |