n | a(n) |
---|---|
0 | 1 |
1 | 1 |
2 | 4 |
3 | 15 |
4 | 61 |
5 | 272 |
6 | 1317 |
7 | 6865 |
8 | 38278 |
9 | 227093 |
10 | 1426921 |
11 | 9457918 |
12 | 65898275 |
13 | 481177881 |
14 | 3672102116 |
15 | 29218285875 |
16 | 241873478425 |
17 | 2079079678176 |
18 | 18524191138689 |
19 | 170803860905237 |
20 | 1627465240969382 |
[1,1,4,15,61,272,1317,6865,38278,227093,1426921, 9457918,65898275,481177881,3672102116,29218285875, 241873478425,2079079678176,18524191138689, 170803860905237,1627465240969382] |