n | a(n) |
---|---|
0 | 0 |
1 | 1 |
2 | 4 |
3 | 15 |
4 | 65 |
5 | 339 |
6 | 2103 |
7 | 15171 |
8 | 124755 |
9 | 1151331 |
10 | 11779971 |
11 | 132323811 |
12 | 1618766691 |
13 | 21421525731 |
14 | 304887173091 |
15 | 4644050174691 |
16 | 75378332568291 |
17 | 1298783923147491 |
18 | 23675771981669091 |
19 | 455240918799307491 |
[0,1,4,15,65,339,2103,15171,124755,1151331, 11779971,132323811,1618766691,21421525731, 304887173091,4644050174691,75378332568291, 1298783923147491,23675771981669091, 455240918799307491] |