n | a(n) |
---|---|
1 | 3 |
2 | 20 |
3 | 120 |
4 | 721 |
5 | 4329 |
6 | 25976 |
7 | 155856 |
8 | 935137 |
9 | 5610825 |
10 | 33664952 |
11 | 201989712 |
12 | 1211938273 |
13 | 7271629641 |
14 | 43629777848 |
15 | 261778667088 |
16 | 1570672002529 |
17 | 9424032015177 |
18 | 56544192091064 |
19 | 339265152546384 |
20 | 2035590915278305 |
[3,20,120,721,4329,25976,155856,935137,5610825, 33664952,201989712,1211938273,7271629641, 43629777848,261778667088,1570672002529, 9424032015177,56544192091064,339265152546384, 2035590915278305] |