The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 12 |
| 5 | 36 |
| 6 | 127 |
| 7 | 491 |
| 8 | 1975 |
| 9 | 7870 |
| 10 | 31298 |
| 11 | 124276 |
| 12 | 500855 |
| 13 | 2061014 |
| 14 | 8699937 |
| 15 | 37534533 |
| 16 | 164436255 |
| 17 | 725855629 |
| 18 | 3210406564 |
| 19 | 14185263492 |
| 20 | 62597467436 |
| 21 | 276260201275 |
| 22 | 1221933146012 |
| 23 | 5426950430555 |
| 24 | 24226437430604 |
| 25 | 108701332822518 |
[1,2,5,12,36,127,491,1975,7870,31298,124276, 500855,2061014,8699937,37534533,164436255, 725855629,3210406564,14185263492,62597467436, 276260201275,1221933146012,5426950430555, 24226437430604,108701332822518] |