n | a(n) |
---|---|
0 | 1 |
1 | 3 |
2 | 12 |
3 | 54 |
4 | 270 |
5 | 1458 |
6 | 8424 |
7 | 51516 |
8 | 331452 |
9 | 2230740 |
10 | 15641424 |
11 | 113846472 |
12 | 857706408 |
13 | 6671592216 |
14 | 53465326560 |
15 | 440602852752 |
16 | 3727748253456 |
17 | 32332181692464 |
18 | 287111706003648 |
19 | 2607272929404000 |
20 | 24187186030419936 |
21 | 228997933855499808 |
22 | 2210786521482955392 |
23 | 21746223198911853504 |
[1,3,12,54,270,1458,8424,51516,331452,2230740, 15641424,113846472,857706408,6671592216, 53465326560,440602852752,3727748253456, 32332181692464,287111706003648,2607272929404000, 24187186030419936,228997933855499808, 2210786521482955392,21746223198911853504] |