n | a(n) |
---|---|
0 | 1 |
1 | 0 |
2 | 3 |
3 | 3 |
4 | 15 |
5 | 30 |
6 | 99 |
7 | 252 |
8 | 747 |
9 | 2064 |
10 | 5973 |
11 | 16995 |
12 | 49089 |
13 | 141414 |
14 | 409755 |
15 | 1188243 |
16 | 3455811 |
17 | 10064952 |
18 | 29368377 |
19 | 85809681 |
20 | 251067645 |
21 | 735446106 |
22 | 2156695533 |
23 | 6330729438 |
24 | 18600079221 |
25 | 54693760680 |
26 | 160951905819 |
27 | 473984678037 |
28 | 1396755865527 |
29 | 4118553190254 |
[1,0,3,3,15,30,99,252,747,2064,5973,16995,49089, 141414,409755,1188243,3455811,10064952,29368377, 85809681,251067645,735446106,2156695533, 6330729438,18600079221,54693760680,160951905819, 473984678037,1396755865527,4118553190254] |