n | a(n) |
---|---|
1 | 4 |
2 | 16 |
3 | 56 |
4 | 250 |
5 | 984 |
6 | 3888 |
7 | 15798 |
8 | 63092 |
9 | 252064 |
10 | 1010554 |
11 | 4040556 |
12 | 16155482 |
13 | 64620946 |
14 | 258358476 |
15 | 1032891644 |
16 | 4129483594 |
17 | 16508060352 |
18 | 65991303276 |
19 | 263798841494 |
20 | 1054506124776 |
21 | 4215228829600 |
22 | 16849633947562 |
23 | 67352986553090 |
[4,16,56,250,984,3888,15798,63092,252064,1010554, 4040556,16155482,64620946,258358476,1032891644, 4129483594,16508060352,65991303276,263798841494, 1054506124776,4215228829600,16849633947562, 67352986553090] |