n | a(n) |
---|---|
1 | 1 |
2 | 4 |
3 | 9 |
4 | 32 |
5 | 71 |
6 | 252 |
7 | 559 |
8 | 1984 |
9 | 4401 |
10 | 15620 |
11 | 34649 |
12 | 122976 |
13 | 272791 |
14 | 968188 |
15 | 2147679 |
16 | 7622528 |
17 | 16908641 |
18 | 60012036 |
19 | 133121449 |
20 | 472473760 |
21 | 1048062951 |
22 | 3719778044 |
23 | 8251382159 |
24 | 29285750592 |
25 | 64962994321 |
26 | 230566226692 |
27 | 511452572409 |
28 | 1815244062944 |
[1,4,9,32,71,252,559,1984,4401,15620,34649,122976, 272791,968188,2147679,7622528,16908641,60012036, 133121449,472473760,1048062951,3719778044, 8251382159,29285750592,64962994321,230566226692, 511452572409,1815244062944] |