n | a(n) |
---|---|
1 | 2 |
2 | 18 |
3 | 118 |
4 | 680 |
5 | 3620 |
6 | 18274 |
7 | 88760 |
8 | 418900 |
9 | 1933904 |
10 | 8775534 |
11 | 39277136 |
12 | 173843142 |
13 | 762388102 |
14 | 3317784992 |
15 | 14344443516 |
16 | 61671799608 |
17 | 263865053452 |
18 | 1124175400716 |
19 | 4771570406736 |
20 | 20185774001256 |
21 | 85141101913670 |
[2,18,118,680,3620,18274,88760,418900,1933904, 8775534,39277136,173843142,762388102,3317784992, 14344443516,61671799608,263865053452, 1124175400716,4771570406736,20185774001256, 85141101913670] |