n | a(n) |
---|---|
1 | 1 |
2 | 4 |
3 | 20 |
4 | 104 |
5 | 560 |
6 | 3080 |
7 | 17199 |
8 | 97120 |
9 | 553146 |
10 | 3171860 |
11 | 18288127 |
12 | 105922544 |
13 | 615820400 |
14 | 3591858480 |
15 | 21008159700 |
16 | 123169357728 |
17 | 723659556026 |
18 | 4259672761560 |
19 | 25115352874780 |
20 | 148302374872080 |
21 | 876876653336922 |
22 | 5191051724957736 |
[1,4,20,104,560,3080,17199,97120,553146,3171860, 18288127,105922544,615820400,3591858480, 21008159700,123169357728,723659556026, 4259672761560,25115352874780,148302374872080, 876876653336922,5191051724957736] |