n | a(n) |
---|---|
-1 | 1 |
0 | 2 |
1 | 6 |
2 | 20 |
3 | 72 |
4 | 272 |
5 | 1056 |
6 | 4160 |
7 | 16512 |
8 | 65792 |
9 | 262656 |
10 | 1049600 |
11 | 4196352 |
12 | 16781312 |
13 | 67117056 |
14 | 268451840 |
15 | 1073774592 |
16 | 4295032832 |
17 | 17180000256 |
18 | 68719738880 |
19 | 274878431232 |
20 | 1099512676352 |
21 | 4398048608256 |
22 | 17592190238720 |
23 | 70368752566272 |
[1,2,6,20,72,272,1056,4160,16512,65792,262656, 1049600,4196352,16781312,67117056,268451840, 1073774592,4295032832,17180000256,68719738880, 274878431232,1099512676352,4398048608256, 17592190238720,70368752566272] |