n | a(n) |
---|---|
0 | 1 |
1 | 0 |
2 | 4 |
3 | 6 |
4 | 20 |
5 | 40 |
6 | 106 |
7 | 238 |
8 | 592 |
9 | 1392 |
10 | 3394 |
11 | 8118 |
12 | 19664 |
13 | 47320 |
14 | 114370 |
15 | 275806 |
16 | 666112 |
17 | 1607520 |
18 | 3881410 |
19 | 9369318 |
20 | 22620560 |
21 | 54608392 |
22 | 131838370 |
23 | 318281038 |
24 | 768402496 |
25 | 1855077840 |
26 | 4478562274 |
27 | 10812186006 |
28 | 26102942480 |
29 | 63018038200 |
[1,0,4,6,20,40,106,238,592,1392,3394,8118,19664, 47320,114370,275806,666112,1607520,3881410, 9369318,22620560,54608392,131838370,318281038, 768402496,1855077840,4478562274,10812186006, 26102942480,63018038200] |