n | a(n) |
---|---|
0 | 1 |
1 | 1 |
2 | 4 |
3 | 20 |
4 | 116 |
5 | 744 |
6 | 5160 |
7 | 39360 |
8 | 350784 |
9 | 3749760 |
10 | 42940800 |
11 | 442713600 |
12 | 4650877440 |
13 | 109244298240 |
14 | 2833294464000 |
15 | -3487131648000 |
16 | -2166903606067200 |
17 | 51809012320665600 |
18 | 6808619561103360000 |
19 | -131306587205713920000 |
20 | -26982365129174827008000 |
21 | 595860034297401409536000 |
[1,1,4,20,116,744,5160,39360,350784,3749760, 42940800,442713600,4650877440,109244298240, 2833294464000,-3487131648000,-2166903606067200, 51809012320665600,6808619561103360000, -131306587205713920000,-26982365129174827008000, 595860034297401409536000] |