n | a(n) |
---|---|
1 | 0 |
2 | 4 |
3 | 9 |
4 | 30 |
5 | 111 |
6 | 355 |
7 | 1257 |
8 | 4357 |
9 | 15146 |
10 | 53379 |
11 | 187699 |
12 | 663631 |
13 | 2352610 |
14 | 8356208 |
15 | 29754352 |
16 | 106127185 |
17 | 379166226 |
18 | 1356700796 |
19 | 4860763378 |
20 | 17436188166 |
21 | 62613987171 |
22 | 225072940410 |
23 | 809789751003 |
24 | 2915986488761 |
25 | 10508369260118 |
26 | 37896284981596 |
27 | 136756217644237 |
28 | 493817776063606 |
[0,4,9,30,111,355,1257,4357,15146,53379,187699, 663631,2352610,8356208,29754352,106127185, 379166226,1356700796,4860763378,17436188166, 62613987171,225072940410,809789751003, 2915986488761,10508369260118,37896284981596, 136756217644237,493817776063606] |