n | a(n) |
---|---|
0 | 1 |
1 | 4 |
2 | 16 |
3 | 56 |
4 | 156 |
5 | 248 |
6 | 1584 |
7 | 2248 |
8 | 18512 |
9 | 51856 |
10 | 189440 |
11 | 609664 |
12 | 2023808 |
13 | 6579712 |
14 | 21441536 |
15 | 69575680 |
16 | 225665024 |
17 | 731127808 |
18 | 2367905792 |
19 | 7666302976 |
20 | 24816189440 |
21 | 80321511424 |
22 | 259955621888 |
23 | 841292972032 |
24 | 2722599796736 |
[1,4,16,56,156,248,1584,2248,18512,51856,189440, 609664,2023808,6579712,21441536,69575680, 225665024,731127808,2367905792,7666302976, 24816189440,80321511424,259955621888,841292972032, 2722599796736] |