n | a(n) |
---|---|
0 | 1 |
1 | 4 |
2 | 18 |
3 | 80 |
4 | 355 |
5 | 1580 |
6 | 7066 |
7 | 31772 |
8 | 143645 |
9 | 652860 |
10 | 2981910 |
11 | 13682328 |
12 | 63046776 |
13 | 291646860 |
14 | 1353967250 |
15 | 6306552800 |
16 | 29464361530 |
17 | 138045441260 |
18 | 648449195350 |
19 | 3053348997200 |
20 | 14409512770575 |
21 | 68143962854836 |
22 | 322886537205062 |
23 | 1532716400556220 |
24 | 7288075248828605 |
25 | 34710221395625380 |
[1,4,18,80,355,1580,7066,31772,143645,652860, 2981910,13682328,63046776,291646860,1353967250, 6306552800,29464361530,138045441260,648449195350, 3053348997200,14409512770575,68143962854836, 322886537205062,1532716400556220,7288075248828605, 34710221395625380] |