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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 6 |
| 3 | 22 |
| 4 | 78 |
| 5 | 288 |
| 6 | 1098 |
| 7 | 4224 |
| 8 | 16432 |
| 9 | 64310 |
| 10 | 253692 |
| 11 | 1003374 |
| 12 | 3992358 |
| 13 | 15908668 |
| 14 | 63684848 |
| 15 | 255153798 |
| 16 | 1026057576 |
| 17 | 4127971346 |
| 18 | 16658240722 |
| 19 | 67237254862 |
| 20 | 272092306164 |
| 21 | 1101134446908 |
| 22 | 4466186295698 |
| 23 | 18113540529096 |
| 24 | 73607652658268 |
| 25 | 299074725301088 |
| 26 | 1217290931946978 |
[1,6,22,78,288,1098,4224,16432,64310,253692, 1003374,3992358,15908668,63684848,255153798, 1026057576,4127971346,16658240722,67237254862, 272092306164,1101134446908,4466186295698, 18113540529096,73607652658268,299074725301088, 1217290931946978] |