n | a(n) |
---|---|
0 | 1 |
1 | 1 |
2 | 1 |
3 | 8 |
4 | 20 |
5 | 84 |
6 | 448 |
7 | 1500 |
8 | 8085 |
9 | 37895 |
10 | 161161 |
11 | 874328 |
12 | 4053140 |
13 | 19724964 |
14 | 103818660 |
15 | 499182288 |
16 | 2574393657 |
17 | 13320605595 |
18 | 66783194335 |
19 | 351243492600 |
20 | 1816922207100 |
21 | 9395207816280 |
22 | 49712099948160 |
23 | 259448325851520 |
24 | 1367225671234800 |
25 | 7260061875376752 |
[1,1,1,8,20,84,448,1500,8085,37895,161161,874328, 4053140,19724964,103818660,499182288,2574393657, 13320605595,66783194335,351243492600, 1816922207100,9395207816280,49712099948160, 259448325851520,1367225671234800,7260061875376752] |