n | a(n) |
---|---|
1 | 0 |
2 | 0 |
3 | 0 |
4 | 0 |
5 | 0 |
6 | 2 |
7 | 4 |
8 | 15 |
9 | 36 |
10 | 108 |
11 | 276 |
12 | 770 |
13 | 2036 |
14 | 5586 |
15 | 15072 |
16 | 41370 |
17 | 113184 |
18 | 312488 |
19 | 863824 |
20 | 2401344 |
21 | 6692368 |
22 | 18724990 |
23 | 52531788 |
24 | 147824963 |
25 | 417006316 |
26 | 1179285900 |
27 | 3342274092 |
28 | 9492427854 |
29 | 27011049612 |
30 | 76999988534 |
[0,0,0,0,0,2,4,15,36,108,276,770,2036,5586,15072, 41370,113184,312488,863824,2401344,6692368, 18724990,52531788,147824963,417006316,1179285900, 3342274092,9492427854,27011049612,76999988534] |