n | a(n) |
---|---|
0 | 1 |
1 | -18 |
2 | 126 |
3 | -420 |
4 | 630 |
5 | -252 |
6 | -84 |
7 | -72 |
8 | -90 |
9 | -140 |
10 | -252 |
11 | -504 |
12 | -1092 |
13 | -2520 |
14 | -6120 |
15 | -15504 |
16 | -40698 |
17 | -110124 |
18 | -305900 |
19 | -869400 |
20 | -2521260 |
21 | -7443720 |
22 | -22331160 |
23 | -67964400 |
24 | -209556900 |
25 | -653817528 |
26 | -2062039896 |
27 | -6567978928 |
28 | -21111360840 |
[1,-18,126,-420,630,-252,-84,-72,-90,-140,-252, -504,-1092,-2520,-6120,-15504,-40698,-110124, -305900,-869400,-2521260,-7443720,-22331160, -67964400,-209556900,-653817528,-2062039896, -6567978928,-21111360840] |