n | a(n) |
---|---|
0 | 1 |
1 | 2 |
2 | 6 |
3 | 26 |
4 | 140 |
5 | 887 |
6 | 6405 |
7 | 51564 |
8 | 455712 |
9 | 4370567 |
10 | 45081476 |
11 | 496556194 |
12 | 5806502663 |
13 | 71734434956 |
14 | 932447207866 |
15 | 12707973761320 |
16 | 181033752071568 |
17 | 2688530124711819 |
18 | 41525910256013832 |
19 | 665674913113633582 |
[1,2,6,26,140,887,6405,51564,455712,4370567, 45081476,496556194,5806502663,71734434956, 932447207866,12707973761320,181033752071568, 2688530124711819,41525910256013832, 665674913113633582] |