n | a(n) |
---|---|
0 | 0 |
1 | 1 |
2 | 4 |
3 | 12 |
4 | 36 |
5 | 120 |
6 | 462 |
7 | 2058 |
8 | 10472 |
9 | 59976 |
10 | 381770 |
11 | 2673374 |
12 | 20422908 |
13 | 169020852 |
14 | 1506427678 |
15 | 14385323610 |
16 | 146527700944 |
17 | 1585801332848 |
18 | 18171944693586 |
19 | 219803766565366 |
20 | 2798628476670180 |
21 | 37414906698747564 |
22 | 524019526485293894 |
23 | 7672827408344428242 |
[0,1,4,12,36,120,462,2058,10472,59976,381770, 2673374,20422908,169020852,1506427678,14385323610, 146527700944,1585801332848,18171944693586, 219803766565366,2798628476670180, 37414906698747564,524019526485293894, 7672827408344428242] |