n | a(n) |
---|---|
0 | 1 |
1 | 4 |
2 | 20 |
3 | 132 |
4 | 1140 |
5 | 11972 |
6 | 143156 |
7 | 1874180 |
8 | 26280820 |
9 | 389655492 |
10 | 6059296564 |
11 | 98301356292 |
12 | 1657846584436 |
13 | 28995059053252 |
14 | 525023523671348 |
15 | 9831325298232068 |
16 | 190226868509537140 |
17 | 3800948683949700036 |
18 | 78387736603554834740 |
19 | 1667727317369199865604 |
20 | 36584269123749323010164 |
[1,4,20,132,1140,11972,143156,1874180,26280820, 389655492,6059296564,98301356292,1657846584436, 28995059053252,525023523671348,9831325298232068, 190226868509537140,3800948683949700036, 78387736603554834740,1667727317369199865604, 36584269123749323010164] |