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| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 2 |
| 3 | 8 |
| 4 | 42 |
| 5 | 208 |
| 6 | 1042 |
| 7 | 5208 |
| 8 | 26042 |
| 9 | 130208 |
| 10 | 651042 |
| 11 | 3255208 |
| 12 | 16276042 |
| 13 | 81380208 |
| 14 | 406901042 |
| 15 | 2034505208 |
| 16 | 10172526042 |
| 17 | 50862630208 |
| 18 | 254313151042 |
| 19 | 1271565755208 |
| 20 | 6357828776042 |
| 21 | 31789143880208 |
| 22 | 158945719401042 |
| 23 | 794728597005208 |
[0,2,8,42,208,1042,5208,26042,130208,651042, 3255208,16276042,81380208,406901042,2034505208, 10172526042,50862630208,254313151042, 1271565755208,6357828776042,31789143880208, 158945719401042,794728597005208] |