n | a(n) |
---|---|
1 | 4 |
2 | 15 |
3 | 209 |
4 | 1116 |
5 | 3807 |
6 | 53985 |
7 | 287844 |
8 | 982255 |
9 | 13927857 |
10 | 74262716 |
11 | 253417919 |
12 | 3593333185 |
13 | 19159492804 |
14 | 65380840911 |
15 | 927066033809 |
16 | 4943074880796 |
17 | 16868003537055 |
18 | 239179443389601 |
19 | 1275294159752484 |
20 | 4351879531719343 |
21 | 61707369328483185 |
[4,15,209,1116,3807,53985,287844,982255,13927857, 74262716,253417919,3593333185,19159492804, 65380840911,927066033809,4943074880796, 16868003537055,239179443389601,1275294159752484, 4351879531719343,61707369328483185] |