n | a(n) |
---|---|
1 | 0 |
2 | 3 |
3 | 15 |
4 | 54 |
5 | 207 |
6 | 783 |
7 | 2970 |
8 | 11259 |
9 | 42687 |
10 | 161838 |
11 | 613575 |
12 | 2326239 |
13 | 8819442 |
14 | 33437043 |
15 | 126769455 |
16 | 480619494 |
17 | 1822166847 |
18 | 6908359023 |
19 | 26191577610 |
20 | 99299809899 |
21 | 376474162527 |
22 | 1427321917278 |
23 | 5411388239415 |
24 | 20516130470079 |
[0,3,15,54,207,783,2970,11259,42687,161838,613575, 2326239,8819442,33437043,126769455,480619494, 1822166847,6908359023,26191577610,99299809899, 376474162527,1427321917278,5411388239415, 20516130470079] |