n | a(n) |
---|---|
1 | 2 |
2 | 1 |
3 | 4 |
4 | 15 |
5 | 66 |
6 | 291 |
7 | 1368 |
8 | 6555 |
9 | 32262 |
10 | 161505 |
11 | 821280 |
12 | 4227710 |
13 | 21996052 |
14 | 115469442 |
15 | 610894004 |
16 | 3253836785 |
17 | 17434360442 |
18 | 93907348819 |
19 | 508194420136 |
20 | 2761768079091 |
21 | 15065823780102 |
22 | 82469439357341 |
[2,1,4,15,66,291,1368,6555,32262,161505,821280, 4227710,21996052,115469442,610894004,3253836785, 17434360442,93907348819,508194420136, 2761768079091,15065823780102,82469439357341] |