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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 4 |
| 3 | 15 |
| 4 | 7 |
| 5 | 209 |
| 6 | 13 |
| 7 | 2911 |
| 8 | 97 |
| 9 | 901 |
| 10 | 181 |
| 11 | 564719 |
| 12 | 193 |
| 13 | 7865521 |
| 14 | 2521 |
| 15 | 6989 |
| 16 | 18817 |
| 17 | 1525870529 |
| 18 | 2701 |
| 19 | 21252634831 |
| 20 | 37441 |
| 21 | 6779137 |
| 22 | 489061 |
| 23 | 4122901604639 |
| 24 | 37633 |
| 25 | 274758906449 |
| 26 | 6811741 |
| 27 | 6575588101 |
| 28 | 1037623 |
| 29 | 11140078609864049 |
| 30 | 40321 |
| 31 | 155161278879431551 |
[1,4,15,7,209,13,2911,97,901,181,564719,193, 7865521,2521,6989,18817,1525870529,2701, 21252634831,37441,6779137,489061,4122901604639, 37633,274758906449,6811741,6575588101,1037623, 11140078609864049,40321,155161278879431551] |