The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 6 |
| 3 | 25 |
| 4 | 105 |
| 5 | 441 |
| 6 | 1848 |
| 7 | 7722 |
| 8 | 32175 |
| 9 | 133705 |
| 10 | 554268 |
| 11 | 2292654 |
| 12 | 9464546 |
| 13 | 39002250 |
| 14 | 160466400 |
| 15 | 659249460 |
| 16 | 2704861755 |
| 17 | 11084629545 |
| 18 | 45375676500 |
| 19 | 185562634950 |
| 20 | 758155908510 |
| 21 | 3094982778030 |
| 22 | 12624593782320 |
| 23 | 51458942047500 |
| 24 | 209609423940150 |
| 25 | 853271593454826 |
[1,6,25,105,441,1848,7722,32175,133705,554268, 2292654,9464546,39002250,160466400,659249460, 2704861755,11084629545,45375676500,185562634950, 758155908510,3094982778030,12624593782320, 51458942047500,209609423940150,853271593454826] |