n | a(n) |
---|---|
2 | 0 |
3 | 0 |
4 | 1 |
5 | 4 |
6 | 17 |
7 | 66 |
8 | 269 |
9 | 1102 |
10 | 4635 |
11 | 19768 |
12 | 85659 |
13 | 375524 |
14 | 1664015 |
15 | 7438862 |
16 | 33515027 |
17 | 152016610 |
18 | 693622315 |
19 | 3181516040 |
20 | 14661568795 |
21 | 67850245684 |
22 | 315187594779 |
23 | 1469195413102 |
24 | 6869889480447 |
25 | 32215398047474 |
26 | 151467333043437 |
27 | 713881813137776 |
28 | 3372142135461789 |
[0,0,1,4,17,66,269,1102,4635,19768,85659,375524, 1664015,7438862,33515027,152016610,693622315, 3181516040,14661568795,67850245684,315187594779, 1469195413102,6869889480447,32215398047474, 151467333043437,713881813137776,3372142135461789] |