n | a(n) |
---|---|
0 | 1 |
1 | 4 |
2 | 16 |
3 | 60 |
4 | 228 |
5 | 864 |
6 | 3276 |
7 | 12420 |
8 | 47088 |
9 | 178524 |
10 | 676836 |
11 | 2566080 |
12 | 9728748 |
13 | 36884484 |
14 | 139839696 |
15 | 530172540 |
16 | 2010036708 |
17 | 7620627744 |
18 | 28891993356 |
19 | 109537863300 |
20 | 415289569968 |
21 | 1574482299804 |
22 | 5969315609316 |
23 | 22631393727360 |
24 | 85802128010028 |
25 | 325300565212164 |
[1,4,16,60,228,864,3276,12420,47088,178524,676836, 2566080,9728748,36884484,139839696,530172540, 2010036708,7620627744,28891993356,109537863300, 415289569968,1574482299804,5969315609316, 22631393727360,85802128010028,325300565212164] |