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| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 7 |
| 3 | 25 |
| 4 | 107 |
| 5 | 381 |
| 6 | 1589 |
| 7 | 5153 |
| 8 | 18809 |
| 9 | 68813 |
| 10 | 256859 |
| 11 | 883247 |
| 12 | 4997167 |
| 13 | 12448095 |
| 14 | 76804553 |
| 15 | 181129817 |
| 16 | 522024177 |
| 17 | 1884097881 |
| 18 | 16163873397 |
| 19 | 38888615377 |
| 20 | 239811969005 |
[1,7,25,107,381,1589,5153,18809,68813,256859, 883247,4997167,12448095,76804553,181129817, 522024177,1884097881,16163873397,38888615377, 239811969005] |