n | a(n) |
---|---|
1 | 0 |
2 | 0 |
3 | 1 |
4 | 2 |
5 | 8 |
6 | 28 |
7 | 98 |
8 | 346 |
9 | 1218 |
10 | 4290 |
11 | 15110 |
12 | 53218 |
13 | 187438 |
14 | 660170 |
15 | 2325166 |
16 | 8189402 |
17 | 28843662 |
18 | 101589450 |
19 | 357805342 |
20 | 1260216122 |
21 | 4438571726 |
22 | 15632968522 |
23 | 55060438334 |
24 | 193926819802 |
25 | 683024192622 |
26 | 2405660280426 |
27 | 8472908349854 |
[0,0,1,2,8,28,98,346,1218,4290,15110,53218,187438, 660170,2325166,8189402,28843662,101589450, 357805342,1260216122,4438571726,15632968522, 55060438334,193926819802,683024192622, 2405660280426,8472908349854] |