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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 7 |
| 3 | 36 |
| 4 | 181 |
| 5 | 907 |
| 6 | 4536 |
| 7 | 22681 |
| 8 | 113407 |
| 9 | 567036 |
| 10 | 2835181 |
| 11 | 14175907 |
| 12 | 70879536 |
| 13 | 354397681 |
| 14 | 1771988407 |
| 15 | 8859942036 |
| 16 | 44299710181 |
| 17 | 221498550907 |
| 18 | 1107492754536 |
| 19 | 5537463772681 |
| 20 | 27687318863407 |
| 21 | 138436594317036 |
| 22 | 692182971585181 |
[1,7,36,181,907,4536,22681,113407,567036,2835181, 14175907,70879536,354397681,1771988407,8859942036, 44299710181,221498550907,1107492754536, 5537463772681,27687318863407,138436594317036, 692182971585181] |