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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 7 |
| 4 | 20 |
| 5 | 21 |
| 6 | 94 |
| 7 | 71 |
| 8 | 328 |
| 9 | 457 |
| 10 | 1194 |
| 11 | 1035 |
| 12 | 7052 |
| 13 | 4109 |
| 14 | 17294 |
| 15 | 33807 |
| 16 | 83984 |
| 17 | 65553 |
| 18 | 389650 |
| 19 | 262163 |
| 20 | 1484820 |
| 21 | 1949717 |
| 22 | 4216854 |
| 23 | 4194327 |
| 24 | 29409304 |
| 25 | 22020121 |
| 26 | 67215386 |
| 27 | 119799835 |
| 28 | 350453788 |
| 29 | 268435485 |
| 30 | 1755807774 |
| 31 | 1073741855 |
[1,4,7,20,21,94,71,328,457,1194,1035,7052,4109, 17294,33807,83984,65553,389650,262163,1484820, 1949717,4216854,4194327,29409304,22020121, 67215386,119799835,350453788,268435485,1755807774, 1073741855] |