n | a(n) |
---|---|
0 | 0 |
1 | 1 |
2 | 4 |
3 | 13 |
4 | 38 |
5 | 105 |
6 | 280 |
7 | 729 |
8 | 1866 |
9 | 4717 |
10 | 11812 |
11 | 29365 |
12 | 72590 |
13 | 178641 |
14 | 438064 |
15 | 1071153 |
16 | 2613138 |
17 | 6362965 |
18 | 15470140 |
19 | 37565389 |
20 | 91125206 |
21 | 220864377 |
22 | 534951112 |
23 | 1294960905 |
24 | 3133261530 |
25 | 7578261181 |
26 | 18323338324 |
27 | 44292046693 |
28 | 107041649438 |
[0,1,4,13,38,105,280,729,1866,4717,11812,29365, 72590,178641,438064,1071153,2613138,6362965, 15470140,37565389,91125206,220864377,534951112, 1294960905,3133261530,7578261181,18323338324, 44292046693,107041649438] |