n | a(n) |
---|---|
1 | 1 |
2 | 4 |
3 | 20 |
4 | 97 |
5 | 459 |
6 | 2187 |
7 | 10442 |
8 | 49861 |
9 | 238068 |
10 | 1136678 |
11 | 5427201 |
12 | 25912833 |
13 | 123723975 |
14 | 590735140 |
15 | 2820536641 |
16 | 13466994652 |
17 | 64299801122 |
18 | 307007207679 |
19 | 1465843189533 |
20 | 6998846289463 |
21 | 33416841401200 |
22 | 159552766705917 |
[1,4,20,97,459,2187,10442,49861,238068,1136678, 5427201,25912833,123723975,590735140,2820536641, 13466994652,64299801122,307007207679, 1465843189533,6998846289463,33416841401200, 159552766705917] |