n | a(n) |
---|---|
0 | 1 |
1 | 4 |
2 | 12 |
3 | 56 |
4 | 244 |
5 | 1396 |
6 | 8200 |
7 | 55092 |
8 | 390216 |
9 | 3005288 |
10 | 24571056 |
11 | 212258216 |
12 | 1939879668 |
13 | 18429618408 |
14 | 184041761768 |
15 | 1891831332208 |
16 | 20301171282452 |
17 | 222742563853912 |
18 | 2534535926617852 |
19 | 29335558770589276 |
20 | 349980362625040712 |
21 | 4228388321175157140 |
[1,4,12,56,244,1396,8200,55092,390216,3005288, 24571056,212258216,1939879668,18429618408, 184041761768,1891831332208,20301171282452, 222742563853912,2534535926617852, 29335558770589276,349980362625040712, 4228388321175157140] |