n | a(n) |
---|---|
4 | 1 |
5 | 4 |
6 | 20 |
7 | 100 |
8 | 560 |
9 | 3416 |
10 | 22764 |
11 | 164640 |
12 | 1286175 |
13 | 10800460 |
14 | 97064396 |
15 | 929872944 |
16 | 9461716810 |
17 | 101926129200 |
18 | 1159018540400 |
19 | 13874662175520 |
20 | 174430929675615 |
21 | 2297878921894800 |
22 | 31655403616078550 |
23 | 455168137467988560 |
24 | 6819445400385661890 |
25 | 106288470495749772120 |
[1,4,20,100,560,3416,22764,164640,1286175, 10800460,97064396,929872944,9461716810, 101926129200,1159018540400,13874662175520, 174430929675615,2297878921894800, 31655403616078550,455168137467988560, 6819445400385661890,106288470495749772120] |