n | a(n) |
---|---|
0 | 1 |
1 | 3 |
2 | 12 |
3 | 56 |
4 | 294 |
5 | 1722 |
6 | 11256 |
7 | 82224 |
8 | 670662 |
9 | 6084578 |
10 | 61030536 |
11 | 672041328 |
12 | 8067200092 |
13 | 104884001796 |
14 | 1468416141744 |
15 | 22026397243680 |
16 | 352422956979270 |
17 | 5991192602253810 |
18 | 107841475915703880 |
19 | 2048988077743637520 |
20 | 40979761692719279220 |
21 | 860574996085362738060 |
[1,3,12,56,294,1722,11256,82224,670662,6084578, 61030536,672041328,8067200092,104884001796, 1468416141744,22026397243680,352422956979270, 5991192602253810,107841475915703880, 2048988077743637520,40979761692719279220, 860574996085362738060] |