n | a(n) |
---|---|
0 | 0 |
1 | 2 |
2 | 4 |
3 | 20 |
4 | 64 |
5 | 248 |
6 | 880 |
7 | 3248 |
8 | 11776 |
9 | 43040 |
10 | 156736 |
11 | 571712 |
12 | 2083840 |
13 | 7597952 |
14 | 27698944 |
15 | 100985600 |
16 | 368164864 |
17 | 1342243328 |
18 | 4893475840 |
19 | 17840411648 |
20 | 65041678336 |
21 | 237125826560 |
22 | 864501723136 |
23 | 3151758405632 |
24 | 11490527150080 |
25 | 41891604733952 |
26 | 152726372368384 |
[0,2,4,20,64,248,880,3248,11776,43040,156736, 571712,2083840,7597952,27698944,100985600, 368164864,1342243328,4893475840,17840411648, 65041678336,237125826560,864501723136, 3151758405632,11490527150080,41891604733952, 152726372368384] |