n | a(n) |
---|---|
0 | 1 |
1 | 4 |
2 | 10 |
3 | 30 |
4 | 74 |
5 | 222 |
6 | 546 |
7 | 1628 |
8 | 3978 |
9 | 11810 |
10 | 28658 |
11 | 84520 |
12 | 203562 |
13 | 596520 |
14 | 1425924 |
15 | 4150232 |
16 | 9838116 |
17 | 28418002 |
18 | 66805554 |
[1,4,10,30,74,222,546,1628,3978,11810,28658,84520, 203562,596520,1425924,4150232,9838116,28418002, 66805554] |