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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 14 |
| 3 | 54 |
| 4 | 236 |
| 5 | 920 |
| 6 | 3730 |
| 7 | 14862 |
| 8 | 59776 |
| 9 | 238856 |
| 10 | 956110 |
| 11 | 3823410 |
| 12 | 15299542 |
| 13 | 61193632 |
| 14 | 244779854 |
| 15 | 979111158 |
| 16 | 3916558030 |
| 17 | 15666093384 |
| 18 | 62664665094 |
| 19 | 250658276292 |
| 20 | 1002634426882 |
| 21 | 4010536846838 |
| 22 | 16042149531756 |
| 23 | 64168594080686 |
| 24 | 256674403929154 |
| 25 | 1026697590590342 |
| 26 | 4106790388347028 |
[1,3,14,54,236,920,3730,14862,59776,238856,956110, 3823410,15299542,61193632,244779854,979111158, 3916558030,15666093384,62664665094,250658276292, 1002634426882,4010536846838,16042149531756, 64168594080686,256674403929154,1026697590590342, 4106790388347028] |