n | a(n) |
---|---|
0 | 1 |
1 | 4 |
2 | 22 |
3 | 140 |
4 | 968 |
5 | 7064 |
6 | 53544 |
7 | 417456 |
8 | 3326304 |
9 | 26967040 |
10 | 221733568 |
11 | 1844667136 |
12 | 15498804480 |
13 | 131325820032 |
14 | 1120928667264 |
15 | 9628975973120 |
16 | 83181462291968 |
17 | 722175844640768 |
18 | 6297942966129664 |
19 | 55143987250677760 |
20 | 484589284705202176 |
21 | 4272491458636754944 |
[1,4,22,140,968,7064,53544,417456,3326304, 26967040,221733568,1844667136,15498804480, 131325820032,1120928667264,9628975973120, 83181462291968,722175844640768,6297942966129664, 55143987250677760,484589284705202176, 4272491458636754944] |