n | a(n) |
---|---|
0 | 1 |
1 | 1 |
2 | 4 |
3 | 15 |
4 | 75 |
5 | 481 |
6 | 4155 |
7 | 47021 |
8 | 647759 |
9 | 10328977 |
10 | 185812755 |
11 | 3715936789 |
12 | 81749718039 |
13 | 1961990821913 |
14 | 51011755028507 |
15 | 1428329124503581 |
16 | 42849873694048287 |
17 | 1371195958107799585 |
18 | 46620662575416672291 |
19 | 1678343852714400808997 |
20 | 63777066403145801007143 |
[1,1,4,15,75,481,4155,47021,647759,10328977, 185812755,3715936789,81749718039,1961990821913, 51011755028507,1428329124503581,42849873694048287, 1371195958107799585,46620662575416672291, 1678343852714400808997,63777066403145801007143] |