n | a(n) |
---|---|
1 | 1 |
2 | 3 |
3 | 9 |
4 | 28 |
5 | 90 |
6 | 306 |
7 | 1078 |
8 | 3984 |
9 | 15228 |
10 | 60580 |
11 | 248556 |
12 | 1055088 |
13 | 4606264 |
14 | 20712888 |
15 | 95550120 |
16 | 452450176 |
17 | 2193051408 |
18 | 10882018224 |
19 | 55166645008 |
20 | 285683655360 |
21 | 1508969248416 |
22 | 8127210649888 |
23 | 44582377997664 |
24 | 249000413522688 |
25 | 1414657929227200 |
26 | 8172653475494976 |
[1,3,9,28,90,306,1078,3984,15228,60580,248556, 1055088,4606264,20712888,95550120,452450176, 2193051408,10882018224,55166645008,285683655360, 1508969248416,8127210649888,44582377997664, 249000413522688,1414657929227200,8172653475494976] |