n | a(n) |
---|---|
0 | 1 |
1 | 1 |
2 | 4 |
3 | 18 |
4 | 94 |
5 | 544 |
6 | 3370 |
7 | 21878 |
8 | 146924 |
9 | 1012222 |
10 | 7114218 |
11 | 50808592 |
12 | 367669254 |
13 | 2689974234 |
14 | 19864822564 |
15 | 147875395930 |
16 | 1108469655350 |
17 | 8359790718480 |
18 | 63387403235682 |
19 | 482935966313310 |
20 | 3695204342149004 |
21 | 28383451250732662 |
[1,1,4,18,94,544,3370,21878,146924,1012222, 7114218,50808592,367669254,2689974234,19864822564, 147875395930,1108469655350,8359790718480, 63387403235682,482935966313310,3695204342149004, 28383451250732662] |