The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 4 |
| 4 | 14 |
| 5 | 28 |
| 6 | 212 |
| 7 | 424 |
| 8 | 3060 |
| 9 | 13488 |
| 10 | 131212 |
| 11 | 262424 |
| 12 | 6444376 |
| 13 | 12888752 |
| 14 | 145241952 |
| 15 | 2146993212 |
| 16 | 40313750564 |
| 17 | 80627501128 |
| 18 | 2265599072684 |
| 19 | 4531198145368 |
| 20 | 173216179971224 |
| 21 | 3202520631881824 |
| 22 | 42018513097187068 |
| 23 | 84037026194374136 |
| 24 | 7051753589203676704 |
| 25 | 50056536119264986708 |
[1,1,2,4,14,28,212,424,3060,13488,131212,262424, 6444376,12888752,145241952,2146993212,40313750564, 80627501128,2265599072684,4531198145368, 173216179971224,3202520631881824, 42018513097187068,84037026194374136, 7051753589203676704,50056536119264986708] |