n | a(n) |
---|---|
1 | 1 |
2 | 6 |
3 | 21 |
4 | 76 |
5 | 249 |
6 | 814 |
7 | 2521 |
8 | 7824 |
9 | 23473 |
10 | 70590 |
11 | 207345 |
12 | 610356 |
13 | 1765959 |
14 | 511006 |
15 | 14643993 |
16 | 41958852 |
17 | 118976633 |
18 | 337823486 |
19 | 951157365 |
20 | 2681163492 |
21 | 7505218171 |
22 | 21030311474 |
[1,6,21,76,249,814,2521,7824,23473,70590,207345, 610356,1765959,511006,14643993,41958852,118976633, 337823486,951157365,2681163492,7505218171, 21030311474] |